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The Lalla Rookh, 585 ; Refitting for a Cruise, 585 ; Non-sectarian 
Education, 590 ; Work on the Yacht, 594 ; Reunion of Comrades 
in the C.U.M.S., 597; President of the British Association, 
597 ; Introduced by Huxley, 599 ; The Address, 599 ; Effects of 
the Address, 609; Helmholtz visits Scotland, 612; Cruising, 
614; Experiments on Ripples, 614; Prolongation of Galvano 
meter Patent, 619; The Western and Brazilian Telegraph Co., 
624 ; Manufacturing the New Cable, 625 ; A Trip to Gibraltar, 
626 ; Elected to Life Fellowship at Peterhouse, 628 ; The 
Hooper, 629 ; Scientific Work, 633 ; James Thomson appointed 
to the Glasgow Chair of Engineering, 634 ; The Hooper sails, 
637 ; The Sounding Machine, 637 ; At Madeira, 637 ; The 
Misses Blandy, 638 ..... 585-639 



A Cambridge Examinership, 640 ; President of the Royal Society of 
Edinburgh, 641 ; Inaugural Address to the Society of Telegraph 
Engineers, 642 ; To Madeira again, 645 ; Engagement to Miss 
Blandy, 645 ; Announcement of the Marriage, 647 ; " Nether- 
hall," 649; Prof. Andrew Gray s Reminiscences, 651; Wreck 
of the La Plata, 654 ; Owens College, Manchester, 655 ; 
Activities of the Period, 658 ; Lighthouses, 658 ; Visits America 
for the Centennial Exhibition at Philadelphia, 668 ; Thomson s 
Reports, 670 ; Bell s Telephone, 670 ; British Association Meeting 





of 1876, 673 ; Helmholtz s opinion of Thomson, 677 ; Proposed 
as Master of Peterhouse, 679 ; The Compass, 679 ; The Sounding 
Machine, 68 1 ; Elected Foreign Associate of the Institut of 
France, 682 ; Electric Lighting and Transmission of Power, 683 ; 
Work on Elasticity, 686 ; Article on Heat, 688 ; Calculating 
Machines and James Thomson s Integrating Mechanism, 692 ; 
Refusal of the Cavendish Chair, 694 . . . 640-695 



Thomson s Love of the Sea, 696 ; His Contributions to Navigation, 
697 ; The Kelvin Compass, 697 ; Defects of the Old Marine 
Compasses, 698 ; Thomson s Improvements, 702 ; His Account 
of the Invention, 705; The Astronomer-Royal s Opinion, 710; 
Admiralty Officials Objections and Apathy, 710 ; Adoption in 
the Navy, 715; James White, Optician, 717; The Sounding 
Machine, 719; The Depth Recorder, 723; Lighthouse Lights, 
724 ; The Tides, 729 ; The Tide-Gauge, Tidal Harmonic 
Analyser, and Tide Predicter, 730 ; Admiralty Committee on 
Ships of War, 731 ; Designs of Dreadnotight and Indomi 
table, 735 ...... 696-735 



Dynamics of Rotation, 736; Experiments on Spinning - Tops and 
Gyrostats, 737 ; Liquid Gyrostats, 740 ; Royal Institution Dis 
course on Elasticity, 743 ; The Vortex-Theory of Matter, 744 ; 
The Gyrostatic Compass, 745 ; Waves, 745 ; Lecture on Waves 
to the Institution of Mechanical Engineers, 748 . 736-752 



Progress of Electric Lighting, 753 ; First Electrical Measuring Instru 
ments, 755; The Standard Electric Balance, 756; The British 
Association of 1880, 760; Revision of T and T , 761 ; The 
Faure Accumulator, 765 ; Promotion of a Company, 769 ; 



Thomson withdraws from the Promotion, 7 70 ; Address and 
Papers at the B.A. of 1881, 770; The Paris Electrical Con 
gress, 775 ; Lighting his House by Electricity, 776 ; The 
adjourned Paris Conference, 787 ; Lecture on Electrical Units to 
the Institution of Civil Engineers, 792 ; Address to the Midland 
Institute, 798 ; Awarded the Copley Medal, 799 ; Further 
work on Units, 800 ; Electrical Instruments, 804 ; B.A. 
Address at Montreal, 806 . . . . 753-809 



The Johns Hopkins University, 810; Invitation to Thomson to 
Lecture, 811 ; The Audience, 814 ; Difficulties of accepting the 
Wave Theory of Light, 8 1 6 ; Equations of Motion in an Elastic 
Solid, 820 ; Difficulties in the Solid Elastic Theory, 822 ; Models 
and their Use, 834 .... ,, ..., 810-839 



Third Refusal to go to Cambridge, 840 ; The Bangor Address, 
845; Electrical Instruments, 846; Professorial Work, 851; 
Royal Institution Discourse on Capillary Attraction, 852 ; 
Politics : The Home Rule Bill, 856 ; Towage of a Boat, 864 ; 
Royal Institution Discourse on Age of the Sun s Heat, 865 ; 
Jubilee of the Electric Telegraph, 869 ; Work on the Partition 
of Space, 873 ; Doings at Netherhall, 876 ; The B.A. of 1888, 
878 ; Presidential Address to the Institution of Electrical 
Engineers, 88 1 ; The Paris Electrical Congress and other 
Activities, 886; The Niagara Commission, 894; President of 
the Royal Society, 897 .... 840-904 



Offer of a Peerage, 905 ; The Name " Kelvin," 907 ; Politics, 
911 ; Takes his Seat in the House of Lords, 913; Arms of 
Lord Kelvin, 914; Lecture on Navigation, 916; Death of 



Professor James Thomson, 918 ; Helmholtz Medallist, 922 ; 
Geological Echoes, 923 ; Account of a Visit to Netherhall, 926 ; 
Death of von Helmholtz, 938 ; Geology, 941 ; The Popular 
Lectures, 946 ; Centenary of the Institut of France, 947 : 
Illness, 953 ; Rontgen Rays, 954 ; The Petroleum Committee, 
962 . . . . . . . 905-963 



The Jubilee of Lord Kelvin, 964 ; The Conversazione, 965 ; 
Presentation of Addresses, 967 ; Conferring of Degrees, 975 ; 
Mascart s Address, 979 ; The Corporation Banquet, 981 ; 
Account of the Ceremonies, 988 ; White s Instrument Factory, 
994 ; Royal Institution Discourse on Contact Electricity of 
Metals, 996 ; The Victoria Institute Address, 997 ; Meeting in 
Toronto, 1897, 1001 ; Death of Principal Caird, 1006; The 
Marconi Company, 1006 ; Visit to Rome, 1009 ; Retirement, 
ion . . . . . . . 964-1011 



Hopes of a Molecular Theory of Matter, 1012; "Failure," 1013; 
A noble Ambition, 1013 ; Early Work, 1015 : Suggestion that 
Heat and Light are Electric, 1018 ; Electricity an essential 
Quality of Matter, 1020 ; Maxwell s Electromagnetic Theory of 
Light, 1 02 1 ; Thomson s Views, 1023; The Vortex - Atom 
Theory, 1027 ; "Steps towards a Kinetic Theory of Matter," 
1032; The Philadelphia Lecture, 1035; The Baltimore Lectures, 
1035 ; B.A. Discussion on Electromagnetic Matters, 1040 ; 
Presidential Address to the I.E.E., 1899, 1043; Abandonment 
of the Vortex- Atom Theory, 1046 ; The Molecular Constitution 
of Matter, 1050 ; Hertz s Work on Electric Waves, 1056 ; 
Rontgen Rays, 1061 ; "Failure," 1072; The Electron, 1074; 
Sir Joseph Larmor s Theory, 1075 ; Further Work, 1076 ; Com 
pletion of the Baltimore Lectures, 1080 . . 1012-1085 




Religious Beliefs, 1086; Views on Life, 1092; Sir Edward Fry s 

Reminiscences of Visits to Netherhall, 1095 ; The Henslow 
Lectures, 1097; Spiritualism, 1104; Vivisection, 1105; Aversion 
from Controversy, 1108; His Humour, mo; Love of Music, 
mo; Precision in Language, 1117; Dr. Hutchison s Reminis 
cences, 1 121; Metaphysics, 1124; Politics, 1128; On University 
Organization, 1131 ; Changes in the Tripos, 1132; On Mathe 
matics, 1133; Newton and Kelvin, 1145 . . 1086-1146 



Phosphorescence, 1147; The End of the Century, 1150; Royal 
Institution Discourse on Clouds over Dynamical Theory, 1152 ; 
Mastership of the Clothworkers Company, 1154; Firm of Kelvin 
and James White, Ltd., 1155 ; The James Watt Oration, 1158 ; 
B.A. at Glasgow, 1160; Death of Tait, 1163; Visit to United 
States, 1164; Privy Counsellor, 1169; Order of Merit, 1170; 
Death of Stokes, 1173; Honorary Degrees at London University, 
1175; and at the University of Wales, 1 1 79 ; Chancellor of Glas 
gow University, n8i ; Eightieth Birthday, 1181 ; B.A. at Cam 
bridge, 1182; Undergoes an Operation, 1187; Unveils Faraday 
Memorial, 1191; Presidency of Institution of Electrical Engineers, 
1195; B.A. at Leicester, 1200; Illness of Lady Kelvin, 1202 ; 
Letters to Mascart, 1 204 ; Last Illness and Death, 1 208 ; 
Funeral in Westminster Abbey, 1209 . . . 1147-1213 


A. List of Distinctions, Academic and other . . .1215 

B. Part I. Printed Books ...... 1223 

Part II. Scientific Communications and Addresses . . 1225 

C. List of Patents . ...... 1275 

INDEX ........ 1279 



BY the purchase of the Lalla Rookh, a smart sailing- 
yacht of 126 tons, Sir William Thomson became 
acquainted with navigation in a new phase. All 
his life he had been fond of sailing ; but by the 
possession of this craft he acquired at first hand a 
most intimate knowledge of seamanship and of its 
needs. For many years the cruises of the Lalla 
Rookh occupied a considerable part of the six 
months between the sessions of the University. 
When the end of October 1870 compelled him to lay 
her up in the Gareloch for the winter, he left her 
with regret. He looked keenly forward to the first 
of May when he should be able to join his ship. He 
was now planning an expedition to the Canaries, to 
be followed by an extensive cruise in the Hebrides 
with a party of scientific friends in the coming 
autumn, and it became necessary to fit out the yacht 
with furniture and bedding. To this end he took 
counsel with Mrs. Tait, resulting in a lively and 
characteristic correspondence : 

VOL. II 585 B 


GLASGOW COLLEGE, March 29, 1871. 

DEAR MRS. TAIT The question, cotton or linen, for 
the Lalla Rookhs berths has, after anxious consideration 
and consultation with naval experts, been decided in 
favour of linen. The cotton fabric seems to be too hygro- 
metric to be suitable for sea-going places. 

Will Glasgow do as well as Belfast for getting such a 
number (or area) as is required ? 

The area for mattress is approximately rectangular, 
and 3 ft. 9 i. by 7 ft. In fixing on the size of sheet I 
would wish to avoid an error which seems to have 
originated in the Levant prior to 725 B.C. (Isaiah xxviii. 
v. 20, second clause * of the v.), and which is still deplor 
ably prevalent at sea. 

I think I ought to have in all 1 2 pr., and therefore (as 
the acct. enclosed shows 4 pr. to be already provided) 8 pr., 
with the proper proportion of pillow slips, would be enough. 
The other things which I want are, so far as I can judge : 

5 dozen towels, equal and similar to those provided by 
you for the N.P.L. [Natural Philosophy Laboratory.] 

6 large bath sheets of similar material. Sometimes 
bath sheets are made thicker (apparently with the idea 
of maintaining a constant proportion of thickness to 
length or breadth), which is a mistake. 

3^ dozen damask table napkins " double damask," I 
understand from T ; , has been decided. 

10 tablecloths. I forgot to measure the table yester 
day when I was at Greenock to see the L. R., now fresh 
coppered and almost ready to be launched, but the 
dimensions will be sent to you by Captain Flarty. I 
think the best quality of damask should be taken for the 
tablecloths, as drops from the skylight, accidents through 
want of steadiness of platform, etc., etc., require the 
strongest resistance against shabbiness of appearance 
that the material can give. 

I should also have a proportionate quantity of glass- 

1 [The verse in question runs "For the bed is shorter than that a man 
can stretch himself on it ; and the covering narrower than that he can wrap 
himself in it."] 

xv THE "LALLA ROOKH " 587 

towels, cook s cloths, and dusters, which, with what I have 
already, should be enough to serve for several weeks away 
from port 

Whatever of the above is to be had best from Belfast, 
will you order it for me ? For the rest, any hints you 
can give will be gratefully received. 

I am not unconscious (but as much as possible the 
reverse) that I am asking a very great benefit, and taking 
advantage to the utmost of the promise you gave me to 
help me, when I write so troublesome a list of wants. 
But you must allow me absolutely to restrict your kind 
ness to ordering the things for me, and directing that the 
hemming and marking be done by the people who supply 
them, and who certainly will, if required, find persons 
ready to undertake those works. 

The Committee on Ships of War will continue its 
sittings during May, and I am afraid much of June, 
partly in London and partly at sea with the Channel 
Fleet. So I must give up Teneriffe for this year, which 
I do with great regret. Will you tell Guthrie l that I 
hope for another visit from him before May, as we got 
scarcely anything of the books done last time, there was 
so much time wasted on tops, etc. Could he not come 
from Ap. 1 8 to 27, which would include an opening 
cruise of the L. R. to Arran, Friday till Monday ? Yours 
always truly, WILLIAM THOMSON. 

The project of an autumn cruise with a party 
of scientific friends is set out in a letter to Helm- 
holtz, terminated by a postscript from Professor 
Tait :- 

GLASGOW COLLEGE, March 30/71. 

DEAR HELMHOLTZ I hope you will be able to come 
to the meeting of the British Association at Edinburgh 
in the first week of August. After it is over (and I wish 
it were over now, as I have the misfortune to be president- 

1 Peter Guthrie Tait, his friend and colleague. 


elect) I want you to come and have a cruise for a few 
weeks among the Hebrides and West Highlands in a 
schooner of 128 X io 6 grammes, which will be my only 
summer quarters besides the new College here. I hope 
Tait will come too, but he has a great aversion to being 
afloat, and without the inducement of your company he 
would scarcely be persuadable. I would also ask Clerk 
Maxwell and Huxley and Tyndall, which would reach 
nearly to the capacity of the Lalla Rookh. Will you let 
me have a line when your plans are fixed ? 

Many thanks for your last letter. I hope the remaining 
anxieties of the campaign in respect to your son soon 
ceased, and that he has got through unhurt. I say nothing 
just now in reply to what you said about the sympathies 
of England. Believe me, yours always truly, 


On the last page of this letter Professor Tait 
wrote : 

DEAR PROF. HELMHOLTZ As Thomson has sent 
this through me, doubtless for some great moral purpose, 
I beg to add that I have no aversion to being afloat, but 
that I prefer to spend my few holidays in active physical 
work, such as the game of golf. Yours truly, 

P. G. TAIT. 

GLASGOW COLLEGE, April 9, 1871. 

DEAR MRS. TAIT Many thanks for your kind letter. 
I do not know the dimensions of the pillows, and could 
not well get them till Wednesday, as they are in store at 
Gourock. I think it would be safe to make the pillow 
slips of the same size as for land pillows, which, I sup 
pose, are something less than 3 ft. 9 in. long. If you 
think so you might let them be made accordingly. But 
in any case I shall have the dimensions of the actual 
pillows despatched by post from Gourock, addressed to 
you, on Wednesday. For the sheets I think 2^ yards 
might be rather short for Guthrie when he comes on a 

xv THE "LALLA ROOKH " 589 

cruise with me. At sea it is desirable to have rather 
more of the sheet to turn over at the top than in beds 
less exposed to acceleration. Three yards would be a 
safe length. Two yards will be a very good breadth, 
sufficient even for sleeping through several tacks. 

I am very sorry to hear that Guthrie has been so ill. 
I cannot think it was good for him to allow Dr. Crum 
Brown to pull out a tooth. We regretted very much his 
not being here to meet Maxwell, Joule, etc. 

Do not let him shirk the August cruise with Helm- 
holtz, Huxley, Tyndall, and Maxwell, who I hope will all 

If the boat race is to be at all, it is right that Cam 
bridge should win, and they seem to have pulled splendidly 
last time. [April I, 1871.] 

I forgot that you had asked about the tablecloths. I 
am in a difficulty about them. I understood from 
Guthrie that the breadth determined the length, each 
being made one and indivisible in certain absolutely 
fixed proportions. I think the length 5 f. 4 i. must be 
when the table is at its shortest. But it is capable of 
prolongation, and I believe about 4 can sit on each side. 
The breadth you have is accurate. I shall write to you on 
Tuesday giving the maximum length. Believe me, yours 

very sincerely, W. THOMSON. 



Tuesday evening [April 1 1]. 

DEAR MRS. TAIT The L. R. table is, I find, of 
invariable length, and the values of the constants which 
you have are correct. Those of the T-cloths which you 
proposed are therefore no doubt perfectly right. 

The pillow-slip question is more difficult. An expert 
who has been employed on board told me that the 
pillows are presumably of the full breadths of the berths. 
If so there will be several different sizes. Captain Flarty 
will send you the length and breadth of each from Gourock 
as soon as possible, by to-morrow evening s post, I hope. 

I write in the greatest haste, as I am just going to sit 


(in the chair) at a meeting to promote united-non-sectarian- 
compulsory education on the same model as the Irish 
national education, which Roman Catholics, Presbyterians, 
and Church-people would not give fair play to in Ireland. 

The gathering referred to was a great public 
meeting in the City Hall. From Sir William s 
speech, as chairman, as reported in the Glasgow 
Herald, the following extracts are taken. After 
reading apologies for absence from influential 
representatives of the Free Church and the United 
Presbyterian Church, he said : 

He believed the feeling was very strong in these Churches 
generally in favour of the views to be advocated that night. 
What the meeting really desired was something very much 
analogous to that which had been given to England in the bill 
for national education which had now become law in that part 
of the United Kingdom. There were certain blots, undoubtedly, 
in the Scottish Education Bill, for what reason he knew not. It 
seemed to be supposed that Scotland required a more denomina 
tional, a more sectarian system of education than England. 
No mistake could be greater than this. Scotland, of all 
countries in Christendom, was the one most prepared, most 
ready to accept a united non - sectarian national system of 
education. Scotland was prepared to make this a thoroughly 
religious system. We were not here in Scotland to have a god 
less education. It would not be a godless education that would 
be supported by the Free Church, the United Presbyterian 
Church, and by the Established Church for the people of Scotland. 
What was desired was, in the first place, education in these 
elements of knowledge and art which were necessary for any 
religious education whatever. What was desired was to make 
religious education possible in the first place by the universal 
teaching of the arts of reading and writing, and to make this 
part of the national education compulsory. It seemed that 
opinion in England was strongly divided with reference to the 
question " compulsory or non-compulsory " ; but, on the other 
hand, it seemed that in Scotland there was a very strong feeling 
indeed among the people that compulsory education was desir 
able. If the people of Scotland desired compulsory education, 

xv THE "LALLA ROOKH " 591 

he felt very confident indeed that they had only to say so, and 
it would be provided for them by Parliament. It was quite 
clear, however, that if education was to be compulsory, the 
national system of education in connection with which com 
pulsory statutes were founded must be unsectarian. There was 
one other point upon which Scotland desired something different 
from that which had ever been provided in England, and that 
was a degree of elasticity in the national system, in virtue of 
which it should not be confined merely to reading, writing, and 
arithmetic. Scotland did not desire schools from which the use 
of the globes should be excluded. A school without maps 
would not be satisfactory in any parish of Scotland, nor would a 
school be satisfactory without music. 

Later, in reference to one of the motions proposed, he said : 
The motion before the house did not propose to exclude the 
Bible from the schools. The Bible was truly and avowedly 
national, and he desired to ask the meeting to say that the 
motion which demanded a provision that no religious 
catechism, or formulary which is distinctive of any particular 
denomination, should be taught in the schools did not apply 
to the Bible. 

At the conclusion the chairman said he wished to call 
attention to the danger that hung over Scotland at present. 
Was Scotland, he asked, to be made the stepping-stone from 
the system of mild denominationalism in England, to utter and 
destructive denominationalism in Ireland ? Unless they resisted 
strenuously the efforts to carry the denominationalism proposed 
in this bill, Scotland would bitterly rue her part in such a 

DEAR MRS. TAIT ^ About April 23 

The L. R., unfortunately, was not ready for my proposed 
cruise at this time owing to the weather, which made 
communication with the shore at Gourock difficult. I 
trust she will be ready by Friday, but ready or not I sail 
on Friday southwards, and hope the E. wind will not 
stop till I reach Land s End. If the linen is not ready 
to cross from Belfast on Thursday it might come leisurely 
to the Admiralty, where I shall be on Wed. week, ditto 
fortnight, do. etc. 

Excuse great haste, and believe me, yours always 



[P.5.] Tell Guthrie I have no time to answer his 
letter to-day as I am overdue to go out to the Rouken. 

On May 5 he was at the Admiralty, but left 
that evening for Plymouth to sail in Plymouth 


L. R. t DARTMOUTH, May 8 [1871]. 

DEAR MRS. TAIT Since writing the above I have 
arrived in London. I made my first attempt to get a 
quiet forenoon of work yesterday in the L. R. (it being 
now Tuesday the pth) which, you may tell Guthrie, was 
very promising, although it only resulted in the miserable 
fiasco of twelve letters all " business," and of the most 
trivial but inevitable kind. However, I hope for better 
things. The only interruption in the course of three 
hours was a great trawler fouling me. The cutter and 
gig had both gone to shore, one for water and the other 
to land J. T. B. and his father, who went to take a walk 
and leave me quiet. The captain, steward, and cook 
were shoving her (the trawler) off when I came on deck 
on hearing the noise, and soon after we got her clear. 
" I hope there s nothing broke, sir ? " " No " (replied 
Captain F.). " I am glad to hear it, sir," were the last 
words from the trawler. I intended to write and give 
you a history of the voyage from the Clyde to Penzance, 
and how thoroughly enjoyed it was by J. T. B. and 
David King, the latter faintly denying that he would 
have enjoyed it still more if she had been on the slip at 
Greenock all the time. J. T. B. was more reticent, but 
I believe felt as deeply. I should also, if I had achieved 
my project of writing to you on board, have given you 
many details of a trip to the Eddystone and a voyage 
from Plymouth to Dartmouth against strong east wind. 
D. K. being replaced by J. T. B. s father. The latter 
remarked that the best thing about yachting was going 
on shore, an opinion in which I by no means concur. 
But all such matters rapidly lose importance, and the 
" log " that is not written during the voyage is never 

xv THE "LALLA ROOKH " 593 

written at all. The one unforgettable thing is the linen 
and the marking of the kitchen towels, than which 
nothing could be better. I never attributed the marking 
to Guthrie, but only the address on the parcel from 

Your most kind letter about the B.A. reached me 
here (London to-day). The five reasons are, each 
separately, irresistible. I shall certainly stay at 17 
Drummond Place if I am able. I shall write as soon as 
I know. Tell Guthrie I am here (London) three days 
of every week l (address Athenaeum Club, Pall Mall). 
Therefore he may give high praise to the L. R. if I get, 
as I intend, two good working days weekly. Tell him 
also that I met Dr. Lyon Playfair just now, who told me 
that he had quite lately seen Dr. N. Arnott, and that the 
latter intends to give 1000 to each of the Scotch Univ ies , 
but that he has taken a crick, and though Mrs. N. A. had 
strongly urged Ed. as well as Glasgow (on account 
of the work done in the P. L? there) he was stiff about 
beginning with Glasgow for a trial. He remarked that 
I had not called the last time I was in London. I hope 
Guthrie s cold is better. Tell him that a good cruise in 
the L. R. will be requisite to brace him against these 
recurring attacks, which seem to be partially (if not 
wholly) due to overdoing the links. Will you not bring 
him with you to London when you come? Even that 
would do him good, and if you would both come from a 
Friday till Wednesday to the L. R. the cure would be 

Monday Morning [May 15, 1871] 


DEAR MRS. TAIT On receiving your most kind 
letter I wrote immediately to my sister 3 to ask if I might 
accept your invitation. I do not mean that I put it 
exactly in that way, but I pointed out forcibly how much 

1 (Four days this week to-day for Admiral Halstead s fleet, and Sir 
Joseph Whitworth s ordnance.) Wed., Thurs., Frid. (from 12 till 5 in the 
Admiralty, except when it is II to 5 on account of extra tediousness of 
witnesses, or 9 till 6 Shoeburyness expedition as last week). 

2 [Physical Laboratory.] 3 [Mrs. King, then resident in Edinburgh.] 


better she would be without me, and I said that you had 
very kindly invited me to stay at 17 D. P. [Drummond 
Place]. I received her answer just before setting out on 
a short tour on the Continent, from which I am now 
returning, and which has prevented me from earlier 
writing to you. I think that as I promised last Septem 
ber to stay with her, and she has Dr. Gladstone only, 
and says she would be greatly disappointed if I did not 
come, I am not free to do otherwise. I could easily 
prove this is a great advantage to you and Guthrie, but 
your letter disarms me, and I can only say that unless it 
were to be very different from all my visits to Greenhill 
Gardens and previous ones to D. P., it would have been 
one of the few pleasures that remain pleasures to me, to 
have the prospect of being at D. P. during the impending 

Often when kept in Glasgow by affairs or by 
his laboratory work, Sir William Thomson would 
retreat for the week-ends to his yacht to gain 
quiet and rest. If he had no relations or friends 
on board he would take his secretary with him, 
that he might get on with work. Rising early he 
would take a plunge, before breakfast, in the sea, 
swimming round the yacht, and in spite of his lame 
leg climb with agility on board by the rope. When 
there were no observations or soundings to take he 
would sit for hours with green book and pencil in 
hand working at calculations and meditating over 
his problems ; or he would pace the deck smoking 
a quiet cigar. Often he would work on far into the 
night. He was a daring navigator, and would sail 
far into the season when other yachts were laid 
up, sometimes in darkness and in severe weather. 
Once when he was sailing in the teeth of a gale 

xv THE "LALLA ROOKH " 595 

his assistant John Tatlock, who often was with him 
as amanuensis, heard Captain Flarty saying half- 
aloud in Sir William s presence : " You will not 
rest till you have your boat at the bottom." He 
took no notice. He never seemed to tire. With 
all the sailors he was extremely popular ; their only 
grievance was that he would sometimes pop up on 
deck in the small hours of the morning to make 
sure that the watch was at his post and awake. In 
all the operations of sailing he took the keenest 
interest, and became a most expert navigator. 
Happy though he was to be thus alone, he was 
still happier if he could secure for a few days cruise 
his brother or some member of their related families, 
nephews or nieces, many of whom retain the most 
joyous recollections of the days spent on board the 
Lalla Rookh. 

Two short extracts from letters to Miss Jessie 
Crum show the use he made of his yacht : 

May i 5. Train, Weymouth to London. Monday morn 
ing. I received your letter on Friday afternoon just as 
I was leaving the Admiralty, and read it in the train on 
my way to Southampton to the L. R. 

May 1 7, Wedy. Athenceum. . . . Soon after daybreak 
(last) Saturday I sailed for Cherbourg ... to Portland 
on Sunday morning. Lord Dufferin is ordered by the 
Queen to Balmoral for 3 weeks, and the Committee is 
therefore adjourned until after the loth of June. I sail 
for Lisbon to-night. 

From Lisbon he sent Miss Crum a long letter 
about his doings there. The Lalla Rookh had 


sailed from Portland to the bar of Lisbon in 6 days 
23 hours. On his return he wrote to Helmholtz : 

THE ATHENAEUM, June 14, 1871. 

MY DEAR HELMHOLTZ I have only this morning, 
on returning to London from a cruise to Lisbon and 
back in the Lalla Rookh, received your letter of the iith 
May. I am very sorry you will not be able to be at 
the meeting of the Association in Edinburgh and many 
others will be sorry also. But I am glad that you will 
come and sail with me in the West Highlands, and I shall 
take care to have the Lalla Rookh in a convenient position 
(probably in the Clyde or possibly Oban), at whatever 
time suits you. I asked Huxley and Tyndall to come 
for a cruise immediately after the meeting, but, unfortun 
ately, neither of them could accept, and I shall therefore 
most probably remain chiefly at the College in Glasgow 
after the meeting until your arrival. You must arrange 
to spend as much as possible of your holiday in Scotland, 
and if you wish to mix a little work with it as you did 
before in Arran, you will find writing not impossible in 
the Lalla Rookh. 

I congratulate you and M me> Helmholtz most sincerely 
on the safe return of your son from the war. Believe me, 
yours very truly, WILLIAM THOMSON. 

On June 24th he writes from the India Office, 
where he has been attending a meeting of the 
Examiners for the India Telegraph Service, telling 
of the progress of his Admiralty work. He is just 
going down to Portsmouth with William Froude to 
sail in the Lalla Rookh to Torquay. He has been 
staying in London with Dr. Gladstone ; J he has 
also given a party, of which he tells Miss Crum, 

1 Dr. John Hall Gladstone, F.R.S., who had married the eldest daughter 
of Dr. David King. 



bringing together several of his old comrades in the 
C.U.M.S. : 

Blow, and Shedden and his wife completed the 
number, six in all. Pollock played the hautboy, Blow 
accompanied on the piano, and Blow played on the 
violin, unaccompanied. He did not play very much, as 
he had been playing in the Crystal Palace (last day of 
Handel Festival) " Israel in Egypt," and was tired, and 
only got up to London for 7.30 dinner. I had succeeded 
in getting the room James Bottomley recommended (as 
the one in which his chemical monthly dinners had taken 
place) and all went off very well. It was a strange 
reunion, like a return from the other world Shedden, 
Blow, Pollock, and myself, who had not been all together 
since the end of 1846, when Pollock, then a new-comer to 
Cambridge, quickly began to be intimate with Blow, 
Shedden, and me, just before Blow and Shedden were 
leaving Cambridge. I have often looked forward to 
such a reunion merely as an occasion when the music 
would have been a happy enjoyment. We had a visit 
from Blow at the Langham Hotel, but could not get any 
opportunity for music. It can never again be what it 
was, and it is too full of sadness for the present. 

On July i, he writes from Cowes that in the 
previous week he had sailed on Monday to Torquay, 
thence up to Southampton. On Wednesday he 
had run up to London to stay the night with 
Pollock at Hampstead. Lord and Lady Dufferin 
have come down to Cowes to yacht with him. " I 
have," he adds, " however, really found the L. R. 
the quietest and best place attainable for work." 
Work meant here the preparation of his Inaugural 
Address as President of the British Association, to 
be held on August 2nd, at Edinburgh. 


To his brother-in-law, Alexander Crum, he 

wrote : 


My B. A. address destroys everything now. I cannot 
write a word of it, but it effectually prevents me from 
writing or doing anything else. . . . Helmholtz is coming 
from Germany for the sole purpose of a cruise about the 
1 2th or 1 5th [of August]. . . . Shedden and his wife, 
W. Young, and a young man (Roberts) from the Nautical 
Almanac office, who has been calculating tides for me (as 
Brit. Ass. Committee) for four or five years, came down 
with me on Saturday for a few days cruise. 

July 1 8. Tuesday (Athenceuni}. . . . landed at 
Portsmouth this morning on my way to London. 

I have made some slight beginnings of actual writing 
for the Address, and have a great mass of matter, greater 
than I shall find space for, to bring in. My difficulty 
will be to get proper arrangement and condensation, and 
I feel as if it must necessarily be a very unsatisfactory 
thing at best. I had George King with me from Satur 
day till to-day. . . . George began the day by reading 
a number of chapters of ist Corinthians, and spent a 
great part of the remainder in writing for me, 1 towards 
the Address. I have taken some of the proceeds to the 
printers to-day, and hope to give some more instalments 
this week. 

I dine with Huxley alone to-day to talk over Asso 
ciation and other matters for the sake chiefly of my 

I shall be here daily till Saturday, but am staying at 
Pollock s, Hampstead. On Sat. I go to the L. R. for 

Sir William Thomson s Presidency of the British 
Association, at Edinburgh, on August 2, 1871, was 

1 [Mr. George King remembers how Sir William paced up and down the 
deck, dictating a few words at intervals, very slowly, making many corrections, 
while the yacht lay becalmed off Bournemouth.] 


an event of great importance. His Address was 
awaited with expectancy, for he was to be introduced 
by none other than Huxley, with whom he had 
crossed swords with knightly courtesy indeed, but 
with deadly earnest, in the matter of Geological 
Time ; and he was known to be opposed to some 
of the developments of the doctrines of Evolution 
that for a decade had been revolutionising men s 
minds as to the origin of things. Nor were the 
expectations of the assembled men of science dis 
appointed ; for the Address, though somewhat 
lengthy and discursive, proved of surpassing inter 
est. The assembly was a brilliant one. Huxley, 
the retiring President, was accompanied on the 
platform by the Emperor Dom Pedro of Brazil, and 
by a crowd of most distinguished savants, British 
and foreign, also by a number of the leading Pro 
fessors of the Scottish Universities. On rising to 
vacate the chair, he expressed cordial thanks to the 
officers and members for the support given to him, 
and congratulated the Association on the good work 
accomplished during the past year. Then turning 
toward the President-elect, he introduced him with 
exquisite courtesy in the words already quoted on 
p. 550 above. 

Sir William Thomson s address began with a 
reference to the origin of the British Association 
and the aims of its founders, in particular Brewster 
and Herschel, the latter of whom had passed away 
but two months before. He also referred to the 
recent death of De Morgan ; to the work of the 


Meteorological Observatory at Kew since its estab 
lishment by the Association in 1842 ; and to the 
need of national laboratories for research. Our 
Government, he declared, fatally neglected the 
advancement of science. Glancing at the Reports 
on different branches of science, which had formed 
a conspicuous feature of the Association s past 
work, he particularised Cayley s Report of 1857 
on Theoretical Dynamics, and Sabine s Report of 
1838 on Terrestrial Magnetism, as having been 
of utmost service to scientific men, as well as of 
practical utility. He suggested the establishment 
of a British Year-book of Science as a need of the 
time. Then, turning to recent advances in par 
ticular branches, he pointed out that many of them 
owed their origin to protracted drudgery. " Accu 
rate and minute measurement," he said, "seems to 
the non-scientific imagination a less lofty and dig 
nified work than looking for something new. But 
nearly all the grandest discoveries of science have 
been but the rewards of accurate measurement and 
patient, long-continued labour in the minute sifting 
of numerical results." He instanced, as cases in 
point, the discovery of the theory of gravitation by 
Newton, that of specific inductive capacity by Fara 
day, that of thermodynamic law by Joule, and that 
of the continuity of the gaseous and liquid states 
by Andrews. Then he turned to the labours of 
Gauss and Weber, who had founded the absolute 
system of measurement of magnetism and electricity, 
and Weber s resulting discovery that the ratio of 


the electromagnetic and electrostatic units is a 
velocity. Maxwell he eulogised for his discovery 
that this velocity is physically related to the velocity 
of light. This led him to reflect how much science, 
even in its most lofty speculations, gains in return 
for benefits conferred by its application to promote 
the social and material welfare of man. " Those," 
he declared, "who perilled and lost their money in 
the original Atlantic Telegraph were impelled arid 
supported by a sense of the grandeur of their enter 
prise, and of the world-wide benefits which must 
flow from its success ; they were at the same time 
not unmoved by the beauty of the scientific prob 
lem directly presented to them ; but they little 
thought that it was to be through their work that 
the scientific world was to be instructed in a long- 
neglected and discredited fundamental discovery of 
Faraday s." Next, dealing with the kinetic theory 
of gases, which he described as the greatest achieve 
ment yet made in the molecular theory of matter, 
he particularly praised Clausius for having thus 
given the foundation for estimates of the absolute 
dimensions of atoms, and of their rates of diffusion. 
Maxwell had completed the dynamical explanation 
of the known properties of gases by bringing in 
viscosity and thermal conductivity. No such com 
prehensive molecular theory had ever been imagined 
before the nineteenth century ; but Sir William 
Thomson was not satisfied. Definite and complete 
as it seemed, it was yet but a part of a still more 
comprehensive theory in which all physical science 



would be represented with every property of matter 
shown in dynamical relation to the whole. But 
there could be no permanent satisfaction to the 
mind in explaining heat, light, elasticity, diffusion, 
electricity, and magnetism by statistics of great 
numbers of atoms, if all the while the properties of 
the atom itself are assumed. " When the theory, of 
which we have the first instalment in Clausius and 
Maxwell s work, is complete, we are but brought 
face to face with a superlatively grand question, 
What is the inner mechanism of the atom ? " This 
at once led to a sketch of the arguments by which 
he himself, in independence of Loschmidt and of 
Johnstone Stoney, had arrived at ideas about the size 
of atoms. He scorned to enter into any questions 
of priority in this affair. " Questions of personal 
priority, however interesting they may be to the 
persons concerned, sink into insignificance in the 
prospects of any gain into the secrets of nature." 
The atom must henceforth not be regarded as a 
mystic point endowed with inertia and attraction, 
nor as infinitely small and infinitely hard. It must 
be regarded as " a piece of matter with shape, 
motion, and laws of action, intelligible subjects of 
scientific investigation." The prismatic analysis of 
light here came in to reveal new facts as to atomic 
constitution. The observational and experimental 
foundations were the discovery by Fraunhofer of the 
coincidence of certain dark solar spectrum lines 
with bright lines in flames ; the rigorous test of 
this by Miller; the identification of the D-lines as 


belonging to sodium ; the discovery of Foucault 
(see p. 224) that the voltaic arc can emit the 
D-rays on its own account and at the same time 
absorb them when they come from another quarter ; 
the teachings of Stokes (see p. 300) as to the physical 
significance of the spectrum lines, and the inherent 
isochronism of the vibrations of an atom ; the in 
ferences from the dark lines as to the chemistry of the 
sun ; the prodigious and wearing toil of Kirchhoff, 
and of Angstrom, of Pliicker, and of Hittorf, in 
preparing spectrum maps and in identification of 
spectra under various physical conditions. The 
chemists, following Bunsen, discovered new metals ; 
biologists applied spectrum analysis to animal and 
vegetable substances ; and the astronomers, led by 
Huggins, carried spectroscopic research to the stars 
and comets. Well might the lecturer point out 
that " scientific wealth tends to accumulation accord 
ing to the law of compound interest." Solar and 
stellar chemistry had garnered great results. Rarely 
before in the history of science had enthusiastic 
perseverance, directed by penetrative genius, pro 
duced within ten years so brilliant a succession of 
discoveries. We were now to have a solar and 
stellar physics : for Miller, Huggins, and Max 
well had shown that the spectroscope afforded a 
means of measuring the relative velocity with which 
a star approaches to or recedes from the earth, and 
had found that not one of them had so great a 
velocity as 315 kilometres per second to or from 
the earth, a most momentous result in respect to 


cosmical dynamics. Then came a brief review of 
the nebular hypothesis of the solar system a 
hypothesis invented before the discovery of thermo 
dynamics, otherwise the nebulae would not have 
been supposed to be fiery. Helmholtz s supposi 
tion of 1854, that mutual gravitation between the 
parts of the original nebula might have generated 
the heat of the sun, had been extended by his own 
further suggestion that gravitation might account 
for all the heat, light, and motions in the universe ; 
while recent spectroscopic observation had shown 
that Tait s theory of comets, in which the head of 
the comet is regarded as a group of meteoric stones, 
furnished at least a probable explanation of that 
feature of their constitution. Astronomy and 
cosmical physics, therefore, well illustrated the truth 
that the essence of science consists in inferring, 
from phenomena which have come under? actual 
observation, the conditions that were antecedent, 
and in anticipating future evolutions. Even 
naturalists of the present day were not appalled 
or paralysed by the prodigious difficulties of acting 
up to this ideal. They were now struggling, boldly 
and laboriously, to pass out of the mere " Natural 
History stage," and to bring Zoology within the 
range of Natural Philosophy. But science brought 
a vast mass of inductive evidence against the 
hypothesis of spontaneous generation, to confute 
the idea that dead matter might have run together 
or crystallized or fermented into organic cells or 
germs or protoplasm. " Careful enough scrutiny 


has in every case up to the present day discovered 
life as antecedent to life. Dead matter cannot 
become living without coming under the influence 
of matter previously alive." " This," said Sir 

William, " seems to me as sure a teaching of 
science as the law of gravitation." " I confess to 
being deeply impressed by the evidence put before 
us by Professor Huxley ; and I am ready to adopt, 
as an article of scientific faith, true through all 
space and through all time, that life proceeds from 
life, and from nothing but life." The passage 
which followed startled even the most advanced 
thinkers present. " How, then, did life originate 
on the Earth ? Tracing the physical history of the 
Earth backwards on strict dynamical principles, we 
are brought to a red-hot melted globe on which no 
life could exist. Hence, when the Earth was first 
fit for life there was no living thing on it. There 
were rocks, solid and disintegrated, water, air all 
round, warmed and illuminated by a brilliant sun, 
ready to become a garden. Did grass and trees 
and flowers spring into existence, in all the fulness 
of ripe beauty, by a fiat of Creative Power ? or did 
vegetation, growing up from seed sown, spread and 
multiply over the whole Earth ? Science is bound, 
by the everlasting law of honour, to face fearlessly 
every problem which can fairly be presented to it. 
If a probable solution, consistent with the ordinary 
course of nature, can be found, we must not invoke 
an abnormal act of Creative Power. . . . When a 
volcanic island springs up from the sea, and after a 


few years is found clothed with vegetation, we do 
not hesitate to assume that seed has been wafted to 
it through the air, or floated to it on rafts. Is it 
not possible, and, if possible, is it not probable, that 
the beginning of vegetable life on the Earth is to be 
similarly explained ? Every year thousands, prob 
ably millions, of fragments of solid matter fall upon 
the Earth. Whence came these fragments ? What 
is the previous history of any one of them ? Was 
it created in the beginning of time an amorphous 
mass ? This idea is so unacceptable that, tacitly or 
explicitly, all men discard it. It is often assumed 
that all, and it is certain that some, meteoric stones 
are fragments which have been broken off from 
greater masses and launched free into space. . . . 
Should the time when this Earth comes into 
collision with another body, comparable in dimen 
sions with itself, be when it is clothed as at present 
with vegetation, many great and small fragments, 
carrying seed and living plants and animals, would 
undoubtedly be scattered through space. Hence 
and because we all confidently believe that there 
are at present, and have been from time im 
memorial, many worlds of life besides our own, we 
must regard it as probable in the highest degree 
that there are countless seed - bearing meteoric 
stones moving about through space. If at the 
present instant no life existed upon this Earth, one 
such stone falling upon it might, by what we blindly 
call natural causes, lead to its becoming covered 
with vegetation. I am fully conscious of the many 


scientific objections which may be urged against 
this hypothesis, but I believe them all to be answer 
able. . . . The hypothesis that [some] l life [has 
actually] originated on this Earth through moss- 
grown fragments from the ruins of another world 
may seem wild and visionary ; all I maintain is 
that it is not unscientific [and cannot rightly be said 
to be impossible]." A brief peroration touched the 
then burning question of Evolution versus Design. 
" From the Earth stocked with such vegetation as 
it could receive meteorically, to the Earth teeming 
with all the endless variety of plants and animals 
which now inhabit it, the step is prodigious ; yet, 
according to the doctrine of continuity, most ably 
laid before the Association by a predecessor in this 
chair, Mr. Grove, all creatures now living on earth 
have proceeded by orderly evolution 2 from some 
such origin." He then quoted from the conclusion 
of Darwin s great work on The Origin of Species, a 
couple of sentences about the numerous forms of 
life plants, birds, insects, worms different, inter 
dependent, yet " all produced by laws acting around 
us," and about the " grandeur in this view of life 

1 The words in brackets were added by Lord Kelvin himself when he 
reprinted the address in 1 894 in vol. ii. of his Popular Lectures and Addresses. 
2 Professor Huxley, in a later discourse, gently brushed aside the im 
portance of Thomson s suggestion in the following words : "I think it will 
be admitted that the germs brought to us by meteorites, if any, were not ova 
of elephants, nor of crocodiles ; not cocoa-nuts, nor acorns ; not even eggs of 
shell-fish or corals, but only those of the lowest forms of animal and vegetable 
life. Therefore, since it is proved that from a very remote epoch of geological 
time the earth has been peopled by a continual succession of the higher 
forms of animals and plants, these either must have been created or they have 
arisen by evolution. And in respect of certain groups of animals, the well- 
established facts of palaeontology leave no rational doubt that they arose by 
the latter method." 


with its several powers having been originally 
breathed by the Creator into a few forms or into 
one, from which endless forms, most beautiful and 
most wonderful, have been and are being evolved." 
Then he continued : " With the feeling expressed in 
these two sentences I most cordially sympathise. I 
have omitted two sentences which come between 
them, describing briefly the hypothesis of the origin 
of species by natural selection, because I have always 
felt that this hypothesis does not contain the true 
theory of evolution, if evolution there has been, in 
biology. Sir John Herschel, in expressing a favour 
able judgment on the hypothesis of zoological evo 
lution, with, however, some reservation in respect 
to the origin of man, objected to the doctrine of 
natural selection that it was too like the Laputan 
method of making books, and that it did not 
sufficiently take into account a continually guiding 
and controlling intelligence. This seems to me a 
most valuable and instructive criticism. I feel 
profoundly convinced that the argument of design 
has been greatly too much lost sight of in recent 
zoological speculation. Reaction against frivolities 
of teleology, such as are to be found, not rarely, 
in the notes of learned commentators on Paley s 
Natural Theology, has, I believe, had a temporary 
effect in turning attention from the solid and irre 
fragable argument so well put forward in that 
excellent old book. But overpoweringly strong 
proofs of intelligent and benevolent design lie 
all around us ; and if ever perplexities, whether 


metaphysical or scientific, turn us away from them 
for a time, they come back upon us with irresistible 
force, showing to us, through nature, the influence 
of a free will, and teaching us that all living beings 
depend on one ever-acting Creator and Ruler." 

Received with great applause, this address evoked 
many perplexities in its hearers. It was known 
that Sir William did not accept the doctrine of 
natural selection ; and many of the orthodox 
Scottish clergy, who looked to him for some pro 
nouncement, were aghast to find him appealing to 
the principle of continuity, and to discover that 
he was an evolutionist who, if he put back the 
origin of life on this earth to some distant globe or 
planet whence it had been meteorically introduced, 
would by an equal logical necessity put it back from 
such globe or planet to one yet more distant, and so on 
ad infinitum ; and they were disposed to regard him 
as a greater sinner against the then popular theology 
than even Darwin himself. Others seemed to regard 
the hypothesis of the meteoric introduction of life as 
a huge scientific joke. 1 Maxwell made it the subject 
of one of his rhyming jeux d esprit, which was sung 
at the Red Lion dinner. For two successive weeks 
Punch poked good-humoured fun at him in verse. 
The issue of August 12, 1871, contained a poem by 
Tom Taylor, entitled : " The Truth after Thomson, 
as versed by a Modern Athenian," a really clever 
summary of the address, from which we cull the 
following sample : 

1 Vide, for example, St. Paul s Magazine, Sept. 1871. 


But say, whence in those meteors life began, 
From whose collision came the germs of man ? 
Still hangs the veil across the searcher s track, 
We have but thrust the myst ry one stage back. 
Below the earth the elephant we ve found, 
Below him of the tortoise touched the ground ; 
But what the tortoise bears ? Dig as we will, 
Beneath us lies a deep unsounded still : 
Sink we with DARWIN, with ARGYLL aspire, 
Betwixt angelic or ascidian sire, 
Though ne er so high we soar, or deep we go, 
The infinite s above us and below : 
Beyond the creeds and fancies of the hour, 
Looms, fixed and awful, A Creative Power. 

In several successive years at the Association 
meetings Sir William reiterated his view. At 
Plymouth in 1877, when a certain meteorite (or 
model of it) was shown, he was keen to explain 
how, though the stone presented marks of fusion 
on the surface, the interior might have remained 
quite cool, so that if there had been in some deep 
crevice of it a bit of moss it would not have been 
burned; or if there had been lurking there a Colorado 
beetle it might have survived to become the father 
of a numerous progeny. Whereupon the witty Dr. 
Samuel Haughton remarked that he would not 
much mind the father-beetle coming in the crevice 
of a meteoric stone if only it had had the foresight 
to leave the old mother beetle at home ! 

The following letter of Feb. n, 1882, shows that 
Sir William persisted in his views. 

nth Feby. 82. 

DEAR DUKE OF ARGYLL I am much interested to 
see that independently you have come to the same con 
clusion regarding the source of all our terrestrial energy 


as I had been forced to come to a long time ago. You 
will see the thing referred to on page 22 of the enclosed 
address. It is more fully developed in an article under 
the title " On Mechanical antecedents of Motion, Heat, 
and Light," which is published in the British Association 
Report for 1854. 

As to the extract from The Times, which I return, 
the writer does not seem to have noticed that while saying 
that ardent faith in the existence of numerous inhabited 
worlds throughout space, such as Sir David Brewster had 
expressed, was more sentimental than scientific, I had 
myself expressed a very strong conviction, not only that 
there is life in other worlds than this, but that some of 
the life in this world is in all probability of meteoric 
origin ; and that I returned to the subject again and 
again in the British Association Meeting at York, and 
obtained the appointment of a Committee to investigate 
meteoric dust, chiefly with a view to ascertaining whether 
any of it contains either traces or actual specimens 
of life. . . . Believe me, yours very truly, 


Sir William Thomson also took part in the 
proceedings of the sectional meetings of the Asso 
ciation, and in presenting the Report of the Com 
mittee on Tidal Observations, added an extempore 
statement as to the determination of the amount of 
tide in the solid body of the globe, which he pro 
nounced to be far more rigid than a globe of glass 
of the same size would be. 

The Association over, Sir William Thomson 
hastened to the quiet of his yacht. During calm 
days he made some extremely interesting observa 
tions on the sets of capillary ripples which are 
originated in water streaming past a fixed narrow 


obstacle, such as a fishing line. These he described, 
with the theory of them, in letters to Tait, dated 
Aug. 1 6 and 23. They are reprinted in Appendix 
G of the Baltimore Lectures, 1904. On the 24th 
he was joined by Helmholtz, who came from 
Germany too late for the meetings. Helmholtz s 
letters to his wife give so graphic a picture of his 
Scottish friends and their activities, that a few 
extracts must be given. The extracts are taken 
from letters ranging from August 20 to Sep 
tember 14 : 

St. Andrews has a splendid bay, with fine sands which 
slope sharply up to the green links. The town itself is 
built on stony cliffs. There is a lively society of sea-side 
visitors, elegant ladies and children, and gentlemen in 
sporting costumes, who play golf. This is a kind of ball- 
game, which is played on the green sward with great 
vehemence by every male visitor, and by some of the 
ladies : a sort of ball game in which the ball lies on the 
ground and is continuously struck by special clubs until 
it is driven, with the fewest possible blows, into a hole, 
marked by a flag, about an English mile distant. The 
entire round over which each party wanders amounts to 
about ten English miles. They drive the ball enormously 
far at each blow. Mr. Tait knows of nothing else here 
but golfing. I had to go out with him ; my first strokes 
came off after that I hit either the ground or the air. 
Tait is a peculiar sort of savage ; lives here, as he says, 
only for his muscles, and it was not till to-day, Sunday, 
when he dared not play, and did not go to church either, 
that he could be brought to talk of rational matters. The 
Browns are also here, and he (Crum Brown) will accompany 
me to-morrow to Sir William. At dinner we had a 
chemist, Andrews, from Belfast, with his wife and daughter, 
and to-day Professor Huxley, the famous evolutionary 


zoologist, all pleasant and interesting people. From Sir 
William we had yesterday two telegrams and two letters, 
to-day two telegrams with changing directions. The 
yacht squadron will sail earlier, and the latest instructions 
are that we go to-morrow evening to Glasgow to sleep in 
Thomson s house at the College, and on Tuesday join the 
yacht squadron at Inveraray on Loch Fyne. W. Thom 
son must be now just as much absorbed in yachting as 
Mr. Tait in golfing. 

(INVERARAY, Aug. 24, 1871.) I came yesterday with 
Professor Crum Brown, who luckily stuck to me till we 
reached the Lalla Rookh, in order to witness here the festivi 
ties of the clans-folk belonging to the Duke of Argyll at the 
reception of their future chieftainess, the Princess Louise. 
On Sunday we had dinner with Crum Brown, with whom 
is staying a great mathematician from London, Sylvester, 
in aspect extremely Jewish, but otherwise an important 
and presentable person. After dinner we had to leave 
the ladies and retreat to the smoking-room ; Tait would 
not allow anything else, but we got on well. Mr. Sylvester 
has been treated by Mr. Gladstone about as badly as 
could have happened at the hands of a Prussian Cultus- 
minister or even worse ; and there was great indignation 
about it expressed by the company. As to their attend 
ance at worship, they all excused themselves, as also did 
the ladies, on account of the rain. On Monday after 
noon I travelled with Prof. Crum Brown to Glasgow. 
In Glasgow we slept in College, where a nephew of 
W. Thomson did the honours. The interior of the house 
was not yet finished, neither carpeted nor painted, full 
of old furniture not yet put into place, and it produced 
an indescribably sad impression, as if no one cared about 
it, in contrast to the old house which Lady Thomson had 
managed. In one corner of the dining-room hung an 
exceedingly fine and expressive portrait of her, and below 
it the couch where she used to lie, and her coverlet. I 
was very sad and could scarce restrain my tears. It is 
very sad when men lose their wives, and their life is left 
desolate. . . . There are about forty yachts assembled 


here, slender and elegantly built ships, and some of them 
tolerably large. Thomson s belongs to the larger sort, is 
a two-master, and is quite commodious. At the moment, 
besides Professor Crum Brown and myself, there are, on 
the yacht, Thomson s two sisters-in-law, another relation 
Houldsworth, and a London physicist Gladstone. My 
cabin is just about so large that I can stand upright in it 
beside the narrow bed : the rest of the space is less lofty, 
yet it contains wash-table, dressing-table, and three 
drawers, so that I can arrange my things well. For 
washing the space is rather small, particularly when the 
ship rolls and one cannot stand firm. To-day we began 
the morning by running on deck wrapped in a plaid and 
sprang straight from bed into the water. After that an 
abundant breakfast was very pleasant. Then came visits 
to the other yachts, and so the day has up to now passed 
very pleasantly in spite of the rain. 

(GLASGOW COLLEGE, Sunday evening, Aug. 27.) Thurs 
day was still worse : we went to lunch on shore although 
the waves were already so high that the yachts began to 
be unsafe at anchor. We saw some Highland sports and 
dances. . . . Yesterday morning there was less wind, 
but sun and rain alternately. The morning was passed 
in preparations for departure, which was accomplished 
about one o clock. Thomson and his men manoeuvred 
the ship very cleverly, and the afternoon was passed 
with tolerably good weather, while we sailed back slowly 
along Loch Fyne. But then the wind caught us, and we 
went at a surprising speed the last two-thirds of our course 
to Greenock, the port for Glasgow. This evening we are 
to go with two nieces of Thomson s to Largs ; Monday 
to Belfast. 

On board the yacht they studied the theory of 
waves, "which," says Helmholtz, "he (Thomson) 
loved to treat as a kind of race between us." 
When Thomson had to go ashore at Inveraray for 
some hours, as he left he said : " Now, mind, 


Helmholtz, you re not to work at waves while I m 

On Aug. 3ist Sir William wrote to his sister, 
Mrs. King, from the yacht in Bangor Bay, County 
Down : 

I am just going to land along with Prof. Helmholtz, 
and Dr. Andrews, who came down last night and slept in 
the L. R.j to see a regatta to-day and accompany us to 
Clandeboye, Lord Dufferin s. We shall be at Clandeboye 
till after dinner to-morrow night, and then sail for Skye. 
Post Office, Portree, and, care of Professor Blackburn, 
Roshven, Fort William, are the best addresses. . . . We 
dined with James on Thursday after Helmholtz had an 
opportunity of seeing Dr. Andrews in his laboratory. . . . 
On Friday morning a party of twelve came down (Dr. 
and Mrs. Andrews and two daughters, Prof. Everett, 
and James and his family, and Mary Bottomley) making 
seventeen in all. . . . Late in the evening, a wonderfully 
beautiful moonlight night, Dr. A., J. T. B., Helmholtz, 
and I, drove down to Cultra and got on board the 
L. R. about midnight. We went on shore to breakfast 
with W. B. at Cultra this morning, and had a fine sailing- 
day for the regatta since. 

A U * 3 1 ) BELFAST. We arrived off Holywood about 
one o clock this afternoon. We do not leave till Sunday 
night about midnight, Lord Dufferin having asked Prof. 
Helmholtz and me to come to his house on Saturday 
to stay over the Sunday. 

After a very pleasant visit to Clandeboye they 
sailed from Belfast on Sunday night, but had very 
bad weather, which prostrated them all "even 
our Admiral," says Helmholtz. The party con 
sisted of Sir William, his brother, his brother-in- 
law, two nephews, and the Geheimrath. They 
visited Oban, Loch Etive, and Tobermory. Thence 


to Roshven, whence Heimholtz wrote on Sept. 
9th : 

W. Th. was very eager to arrive here, where his 
colleague Mr. Blackburn, Prof, of Mathematics in 
Glasgow, has a lonely property, a very lovely spot on a 
bay between the loneliest mountains. The Atlantic 
showed itself this time very friendly, and we came quickly 
here, so that in the afternoon we could take an excursion 
with the family and dined with them. ... I expect 
that in the next day or so we shall abruptly begin 
our return, for Sir W. is very undecided as to the north 
side of Skye. . . . Mrs. B. has a remarkable talent for 
painting animals. She fashions all her doings and house 
hold ways to suit her professional tastes. ... It was 
all very friendly and unconstrained. W. Thomson 
presumed so far on the freedom of his surroundings 
that he always carried his mathematical note-book about 
with him, and as soon as anything occurred to him, in 
the midst of the company, he would begin to calculate, 
which was treated with a certain awe by the party. How 
would it be if I accustomed the Berliners to the same 
proceedings ? But the greatest naivete of all was when 
on the Friday he had invited all the party to the yacht, 
and then as soon as the ship was on her way, and every 
one was settled on deck as securely as might be in view 
of the rolling, he vanished into the cabin to make calcula 
tions there, while the company were left to entertain each 
other so long as they were in the vein ; naturally they 
were not exactly very lively. I allowed myself to seek 
amusement in balancing myself up and down on the deck, 
in wavering grace, and occasionally setting cataracts of 
sea-water to run off my waterproof. 

After cruising in the Sound of Skye they 
returned through the Sound of Mull, where, 
being becalmed, they made experiments on the 
velocity of propagation of the smallest ripples 



that can be formed on water, and so back to 


L. R., LARGS BAY, Oct. 29, 71. 

DEAR HELMHOLTZ I have too long omitted to 
write to Du Bois Reymond in acknowledgment of the 
notice he sent me of my having been elected to the 
Berlin Academy. I received it on my way through 
Glasgow to the L. R. after the British Association, and left 
it in the house, which is now all in confusion, being handed 
over to painters and paperhangers. It may be some 
time yet before I can find the official intimation, and as I 
am anxious not to delay writing to Du Bois Reymond, 
you would oblige me much by telling me what is the 
proper designation of the Academy ? Imperial ? Royal ? 
Berlin Academy of Sciences, I presume ; also what is 
the designation of my own appointment corresponding 
member ? foreign member ? 

I hope you found all well at home when you arrived, 
and that all " went well " in respect to the marriage. I 
suppose you are now fairly launched on your University 
" Semester." Our " session " commences to-morrow week, 
and by this day week the Lalla Rookh will be at her 
winter moorings in the Gareloch. I have lived on 
board ever since you left (not merely because my house 
has been uninhabitable), but except two trips to Loch 
Fyne and two to Arran I have been chiefly between 
Largs and Greenock, and working hard at my reprint 
etc. of Electrostatics and Magnetism, which I am anxious 
to get launched before Christmas. It has been " on the 
stocks " for about five years. 

You should look at Cauchy and Poisson on Waves, 
the Concours de 1815, when you have time. The point 
lies in the evaluation of the function 


cos mx* cos (/ ijgm)dm 

(for the case of motion in two dimensions) ; considered as a 
function of x it is a fluctuating function of a very curious 
character. We must have it tabulated by the British 


Association s Function -calculating Committee. Cauchy 
makes the thing very clear. Poisson I don t know 
so well yet. Both would be greatly improved by 
diagrams showing the forms of the waves and the laws 
of variation at different depths, etc. I was under a 
misapprehension when I spoke to you lately on the 
subject. I thought that a single disturbance at a point 
or along an infinite straight line, such as is produced 
by dipping a solid into water and not raising it out, but 
leaving it at rest, could not cause oscillations. What 
it does really is to cause a positive swell to spread out 
in each direction, followed by a series of undulations, 
negative and positive, finer and finer, and at any one 
place of the water, becoming finer and finer in length from 

crest to crest ultimately in proportion to ^ After ten or 

twenty waves have passed a point at distance x from the 
place of disturbance, the wave length (in the case of 
motion in two dimensions) is very approximately 


or iirx\ 


where x must be a large multiple of the diameter of the 
disturbing body, but a small fraction of \gfi. 

Did you meet Strutt * when you visited his family in 
England ? I hear that he would have been the new 
professor in Cambridge if Maxwell had not accepted. 
Believe me, yours always truly, 


On Nov. 2, still cruising off Largs, he wrote to 
Professor Andrews that he was awaiting Napier 
to make trials of his pressure - log, after which 
the yacht was to sail to winter quarters in the 

At the end of the cruising season he wrote to 
Dr. J. Hall Gladstone: 

1 Lord Rayleigh. 


GARELOCH, Nov. 4, 1871. 

MY DEAR GLADSTONE You have heard from my 
sister that I am to be in London this day week. Even 
should it not be convenient to you to let me stay with 
you this time, I hope to have the pleasure of seeing you 
in the course of the few days that I shall be in London. 
I do not, however, wish to delay so long answering about 
the Tidal Committee in reply to Mr. Unwin s letter. The 
present Committee of the British Association on Tides is 
a new one, which was appointed about four years ago, 
and has been continued from year to year since that time, 
with grants of money for calculating results of observa 
tions such as those given by tide-gauges, and generally 
for promoting the investigation of tides. . . . 

The Committee will be glad to receive the curves of 
the Calcutta Tide-gauge, and to apply the method of 
reduction which we have been following if we find that it 
can be done with advantage. . . . 

I am now on the point of " flitting," as we say in 
Scotland, from my summer quarters on board the Lalla 
Rookh to the College. I am alone with one man on 
board waiting for my train, the others having just sailed 
away in the " cutter " and " gig " for Greenock to leave the 
boats there for the winter, and to find places, chiefly 
no doubt in foreign going ships, for themselves. . . . 
Believe me, yours always truly, 


The business in London was a petition for the 
prolongation of the patent for the mirror galvano 
meter. Sir John Karslake, Q.C., was counsel for 
the petitioner ; Mr. Archibald for the Crown. Six 
weeks later Sir William wrote to his assistant, Mr. 
Leitch, who was in charge of the recorder at Suez : 

Dec. 14, 1871. 

MY DEAR LEITCH . . . Ten days ago the Privy 
Council gave me a prolongation for 8 years of my 


1858 patent. My formal petition for the prolongation 
was made last summer, and the three cis-Indian and the 
three ultra - Indian Companies all lodged objections. 
They, however, withdrew their objections before the 
petition was heard, and promoted rather than opposed 
my case. I also got assistance from Sir C. Lampson, 
who was deputy -chairman of the Atlantic Telegraph 
Company, and from Mr. Saward, their secretary. Also 
Mr. Willoughby Smith, Sir James Anderson, Sir Daniel 
Gooch, Captain Sherard Osborne, Mr. Fender, and other 
influential people in the companies were favourable. . . . 
Yours truly, W. THOMSON. 

Further details are given in a letter to Miss 
Jessie Crum, then abroad : 


DEAR JESSIE I have been hearing of you all in 
several indirect ways, the last of which was Mary s letter 
to Dr. Rainy, which he brought to me one day. I hope 
you are getting on well, and feeling comfortable in your 
villa. I should be much obliged by a letter from either 
you or Mary, when you have time to write. You must look 
upon this simply as a begging letter. I cannot give any 
thing in return for what I have been asking, as the things 
I have been kept incessantly busy with are dull and 
uninteresting, except so far as getting through little by 
little what must be done is interesting. 

I was in London again from Saturday last till Wed 
nesday about my petition for prolongation of my 1858 
patent. I had been warned by Grove (who was my 
counsel until he was promoted to be a judge) to expect 
nothing, and to consider that even a prolongation for one 
year would be a good result. The Privy Council gave 
8 years. The case altogether went off very well. The 
judges early intimated that they did not require any 
more evidence as to the " merits of the invention," and 
they showed a liberal spirit in respect to accounts, etc. 


Varley had prepared an admirable apparatus for illus 
trating the action of my mirror instrument, and showed it 
in action to the judges, which had a very good effect. 
The Telegraph Companies (8 now in all) with whom I 
have come to agreement are all very pleasant and friendly, 
and the new instrument is making its way eastwards 
(now as far as Suez, and going off to-day to Aden and 
Bombay). Until the time when I was coming home from 
Brest, when we were at Barra House, there was nothing 
settled. As soon as anything should be settled, it went 
into unsettlement, with another prospect of a lawsuit, again 
up till that time. I well remember the warm congratula 
tions and sympathy we had when we hurried home from 
Kissingen the year before, and things seemed to be settled 
in London. Then I went off again, and all the winter 
we were in Edinburgh it was a subject of anxiety to my 
dearest Margaret. It was not till the August following 
that I could tell her it was all settled. Since that time 
those things have gone as prosperously in every respect as 
possible ; but she only knew the perturbations and toils, 
from some of which she suffered greatly by over-fatigue 
going to Valencia in 1858. Near the end of April, when 
very good accounts of the new instrument came from St. 
Pierre, and the Indian Companies were all wanting to 
have it, she said, " It is just the fruit of your labours." 

I must stop now, and go on with my book on 
Electricity, which is chiefly compiled from things written 
more than twenty years ago, and some which I wrote in 
Edinburgh the last winter we were there. Macmillan is 
pressing me to get it out by Christmas, if possible, and I 
am at it every moment of spare time. 

With love to your mother and Mary, I am, yours 
always affectionately, WiLLIAM THOMSON. 

In January 1872 Sir William was busy over the 
proofs of his reprint of papers on Electrostatics and 
Magnetism, which had been on hand for four years. 
In February he was in London with Dr. Gladstone ; 


then went to Edinburgh to work with Tait at proofs 
of the smaller Elements of Nat^lral Philosophy, for 
the Oxford Press (see p. 472). 

On March 29 he wrote of his doings to 
Miss Jessie Crum : new cable schemes, trials of 
telegraph instruments old and new, correspond 
ence "with my old friend De Sauty, and several 
others of the old Atlantic people, who are all 
much taken up with the recorder, and (under 
instructions from Sir James Anderson) doing their 
best to get it to work well." He is proposing a 
short spring cruise before session ends, and then 
to sail to Gibraltar to see the recorder working 
there. He has a prospect, after the British Asso 
ciation is over, at the end of August, of going to 
Quebec with Dr. Norman Macleod, but the project 
was cut short by the death of Dr. Macleod in June. 
Two of his nephews will be required as lieutenants 
in the new Atlantic cable scheme. " There is 
quite an epidemic amongst the laboratory students 
of desire to become telegraph engineers." 

Then comes a commercial shadow across the 



DEAR JENKIN I am sorry to hear what you tell me. 

I have no confidence in B , and would require any 

statements as to the use of the mirror to be very carefully 
sifted before we can admit them. It would be necessary 
for him actually to have used the mirror on the cable, 
and also at a time found inconsistent with my claims, 
before we could admit any weight to the objection to our 
rights. Find out, if possible, taking whatever law advice 
is necessary, to what extent experimental use of an 


invention in that way, confessedly mine, can invalidate 
my claim. If he only experimented with it on the cable, 
and did not use it for practical working on the line, I do 
not believe his objection will be valid. Try, however, if 
possible, should the case look bad against us, to make 
a compromise, as the companies no doubt admit the 
moral right. Of course we know that directors can t be 
generous with their shareholders money, but the proper 
mixture of generosity and worldly wisdom, escaping 
litigation, and procuring us as allies and assistants to 
their signalling arrangements, may commend itself to 
them. We have another string to our bow in the 
recorder. For all their lines it must cut out the mirror, 
and that speedily. But be cautious in using or showing 
this string. If we can get our terms for the mirror con 
sented to, we can make more use of our recorder rights 
than if we put them forward now. In the course of six 
months, I believe, I could give thorough good recorders 
for their lines. You may feel confident as to this, and 
use it as you think best. Yours truly, 


By April 1 1 he is able to send word to Leitch 
that Sir James Anderson now considers the re 
corder to be the instrument for all their cable 

On April 28 he writes again, from London, he 
has been suddenly called up on business of the 
" Great Western Telegraph Co."; that he intends 
to go to J. T. Bottomley s marriage at Belfast ; 
and that on Friday he hopes to be at rest on his 
yacht in the Gareloch, ready to put to sea. He is 
wishing to sail for Gibraltar as soon as possible, 
that he may be free to go later to Bermuda. " On 
Friday I got the last MSS. of the book out of 


The Great Western Telegraph Company was a 
project to lay a cable via Madeira and the Bermudas 
to Boston and to the West Indies ; but later by 
arrangement with the earlier companies the project 
was altered, though the cable for this work had 
been manufactured and the ship Hooper specially 
designed for laying it ; and it became merged in the 
Western and Brazilian Telegraph Co., which laid 
cables in five sections from Para to Rio Janeiro, 
touching at Pernambuco. Eventually this and 
other South American cables were taken over by 
the London Platino- Brazilian Telegraph Company. 

About June ist Sir William wrote to Helm- 
holtz :- 


DEAR HELMHOLTZ I am going to Scotland 
to-night, and return to London about the middle of next 
week, to spend two days in this house (of Mr. Spottis- 
woode, President of the London Mathematical Society). 

On Saturday the 2ist I hope to sail from Torquay 
for Gibraltar, and to call at London on my way back, 
visiting the telegraph stations at both places, my recorder 
being now in constant use there. 

There is now a great telegraph project in the course 
of execution to lay cables from England to Bermuda, and 
then to New York and St. Thomas. The manufacture 
of the cables has commenced, and Fleeming Jenkin and 
I being engineers to the Company are obliged one or 
other of us to be very frequently in London. We have 
a great deal of electric testing to do insulation, electro 
static capacity, and resistance of the copper conductor, 
also testing the strength of the iron wire and of the 
finished cable. The laying will not be commenced till 
this time next year. I am living chiefly on board the 
Lalla Rookh) off the south of England, and coming up to 



London when necessary. I can only get mathematical 
work done in the yacht, as elsewhere there are too many 

A few days ago I despatched the very last of my 
volume of Electrostatics and Magnetism to the printers, 
except the preface, and I am now getting to work on 
Vol. II. of the Natural Philosophy, and the reprint of 
Vol. I. 

I hope you have been well, and your family all well, 
since we parted at the " Albert Quay." Is your new 
laboratory finished or making satisfactory progress ? I 
hope it will turn out in all respects satisfactory to 
you. Believe me, yours very truly, 


By this time the new company was fairly afloat, 
and the partners had to keep a staff of electricians 
at work, some at Millwall, others at Mitcham under 
David T. King, to superintend the manufacture. 
Sir William had to spend two or three days each 
week at the works. He has a way of turning up at 
the Millwall works on a surprise visit, arriving once 
at 2 A.M. in a dripping mackintosh, with a black bag 
in his hand, "for all the world like a tea-traveller," 
as one of the assistants writes. He is living the 
rest of his days on his yacht, cruising round 
Torquay, or taking his friends Dr. Gladstone, 
Mr. Varley, and Dr. Siemens trips to Sheerness 
or Margate. He varied these amusements by 
reading to the London Mathematical Society a 
paper on the reduction of Polynomial Quadratics, 
which he had worked out in the quietude of his 

On June 24th he wrote to Lord Rayleigh, from 


Torquay, respecting certain paragraphs of " the 
book " : 

I am on the wing for Gibraltar (and other telegraph 
stations Lisbon, Brest if time before the B. A., Brighton, 
Aug. 14, permits). I hope to despatch from Gibraltar all 
I have to say in the way of additions or amendments to 
the first two or three sheets of Vol. I., so that the reprint 
may go on forthwith. Meantime, or as soon as possible, 
amendments or suggestions for early parts or any part of 
the volume sent to Tait will be thankfully received. 

Then he sails for Gibraltar one Sunday morning 
from Gravesend. But just as they weigh anchor 
the " Thames Mission " boat comes up, and Sir 
William orders Captain Flarty to stop the yacht 
while the minister conducts service for them on 
board. By June 24th he has got to Torquay, and 
has taken aboard the new recorder for Gibraltar, 
and some new instruments for sounding and for 
measuring speed at sea. While he is away affairs 
at home do not flag. White is pushing on with im 
proved recorders; and Donald MacFarlane, writing 
him to report progress of the laboratory work in 
the new building of the University, says : " I have 
taken possession of the spare room above the stair 
case (without leave), and in one corner of it I have 
stowed all the packing-boxes which were always in 
the way." 

Returning to England, August ist, he writes in 
the train, from London to Torquay, to his sister-in- 
law a detailed account of his tour : 

I have had a very pleasant and satisfactory cruise, and 


made useful as well as interesting visits to the three tele 
graph stations, Gibraltar, Lisbon, and Porthcurno (though 
only three hours at the last in consequence of a letter, 
reinforced by a telegram, summoning me to attend a 
meeting of the " Great Western Tel." Board in London 
yesterday). At Gibraltar my old enemy, but now very 
good friend, De Sauty, who was at the other end of the 
cable in 1858, has managed admirably with the recorder, 
and has entirely given up the mirror in all the work of 
the station. I found him as agreeable and obliging as 
possible in every way. We were almost constantly at 
work in the telegraph office from the Sunday * morning, 
when I arrived, till the Saturday morning, when I sailed 
for Lisbon. . . . 

The rest of the letter is full, moreover, of lively 
details about the monkeys on the Rock of Gibraltar 
that came early in the morning to visit the telegraph 
station there ; of his trip towards Algiers in the Lalla 
Rookh with De Sauty on board ; and of his voyage 
home via Lisbon. To-morrow he will sail from 
Torquay to Cowes for the R. Y. S. Regatta. 

Brighton was the scene of the British Associa 
tion meeting of 1872, and Sir William went there 
for three days to introduce his successor, Dr. 
Carpenter, into the presidential chair, and to read 
two papers one on the Identification of Lights at 
Sea, the other on the Use of Steel Wire for Deep 
Sea Sounding. In the latter he narrates how in 
the Bay of Biscay he has corrected the charts, using 

1 " Particularly the Sunday, which at all the stations of submarine lines is 
the great day for testings and adjustments, lawful on the ground of necessity 
and mercy. About five o clock on the Sunday the cable has generally done 
its week s work, and is nearly at rest till about eleven on Monday forenoon ; 
but for three weeks together it has been never once clear, which is about as 
bad as Mr. Pickwick s cab horse," 


a lead sinker of only thirty pounds at the end of a 
three-mile line of thin pianoforte wire. 

At the Mathematical and Physical Section, in 
proposing a vote of thanks to the president, who 
had referred to Professor Zollner s electric theory 
of comet s tails, he told how some time since, at a 
workmen s philosophical institute at Millwall, an 
intelligent man produced a glass tube which 
cracked when an iron wire was laid along its 
inside. The workmen were puzzled by the fact, 
but at last agreed that it must be electrical ! The 
same merit lay at the bottom of Zollner s theory, 
namely, omne ignotum pro electrico. 

More cruising about the Clyde completes the 
holiday, and in September he is back at the 

In October 1872 Sir William Thomson was 
elected to one of the two life Fellowships at Peter- 
house, founded for men distinguished in Science 
or Letters ; the eminent Greek scholar, Richard 
Shilleto, having been elected to the other in 1867. 

There was now big work in hand over the 
manufacture of the new cable, and the building of 
the cable-ship for laying it. He seeks advice from 

his engineering brother : 



Oct. 30, 1872. 

MY DEAR JAMES Hooper s Telegraph manufactur 
ing company have ordered for cable laying a ship 
350 ft. long, 55 ft. beam, 36 ft. moulded depth; builders 
measurem 1 = 4940 tons. 


Jenkin and I both strongly urge a hydraulic arrange 
ment to give power of manoeuvre that is to say, a pump 
and water pipes to give means of 
discharging water perpendicu- 
larly across the length at any 
one of four places, A, A , B, B , 
or at two of them simultaneously. I calculate that 
water discharged through an aperture of J square metre 
(say 2^- square feet) at a velocity of 6^ metres per 

second, that is to say, -5 or i~ tons per second, would 

4 16 

give a pressure of one ton. I would wish to be able to 
give at least I ton simultaneously at A and B, and 
therefore would need to be able to discharge not less 
than 3^- tons per second, or 728 gallons per second, or 
say 44,000 gallons per minute. The head of water 
corresponding to the discharge velocity of 6j metres per 

(6 1 ) 2 
sec. is g = 2 metres. I should be much obliged by 

your telegraphing to me to above address on Friday 
morning your opinion as to the centrifugal pump and 
water-ways that would be required for this, and your 
opinion regarding Gwynne s pumps, of which I send you 
printed prospectus by same post with this. You might 
also write to me on Friday, addressing St. Peter s College, 
Cambridge. . . . The ship is to be made by Mitchell, 
Newcastle, and it is to be finished and round in the Thames 
by 26 April, subject to 100 penalty per day for delay 
after that date. 

I was made a Fellow of Peterhouse under a new statute 
which allows men eminent in literature or science to be 
elected independently of marriage. I shall go back to 
Cambridge on Saturday on my way to Glasgow. Your 
affectionate brother, W. THOMSON. 

GLASGOW COLLEGE, Nov. 5, 1872. 

DEAR JAMES I think the hydraulic thwart ship 
propeller, according to the data of your telegram, will do. 
I spent yesterday at Newcastle with the shipbuilder (Mr. 


Swan of " Mitchell and Co."), and he has found a place 
for it ... [here follow ten octavo pages of details] . . . 
The thing is of extreme urgency, as in three weeks the 
plating of the ship about the stern will have commenced. 
Many of the frames are up already. I only heard on 
Thursday last that she was to be built. I wish they had 
told me beforehand, and I would have had a thwartship 
propeller in the original plans, which would have saved a 
good deal of money on what will have now to be spent to 
get it applied. Your professional charge and expenses 
must be charged, with the wheel and work of the ship 
builders putting it in, to Hooper s Company. If we can 
get a practicable scheme, it is, I think, certain that the 
Company will adopt it In haste, your affec 1 brother, 


\Nov. 1 8, 1872, Post-mark]. 

DEAR JAMES Thanks for your telegram. Mitchell s are 
quite confident about thwartship screw below main screw 
shaft, 6 ft. diameter of screw. Three blades to be driven 
by a wire rope round grooved rim 6 ft. diameter surround 
ing blades of screw. You will receive in a few days from 
me (or from Mr. Froude) their drawings. 

The engine is to be on deck, and I have a telegram 
from them to-day (scarcely time to have read it yet) to 
effect that we may have 60 Ibs. pressure, and no limit to 
size of cylinders. Yours, W. T. 

Great haste. 

Sir William was at this time living in his half- 
furnished residence in the professors court at the 
University, his nephew, James T. Bottomley, resid 
ing with him and acting as assistant in his laboratory 
work and teaching. A well-known feature of his 
household was " Dr. Redtail," a grey parrot with 
red tail feathers, who had been bought in Seven 
Dials. Of this favourite bird many stories are told. 


The best authenticated is his greeting of his master 
as he hurried in from the laboratory to join an in 
vited party at lunch : " Late again, Sir William ! 
Late again ! " 

At the end of the year he has a proposal to convey 
to Helmholtz : 

Dec. 2, 1872. 

DEAR HELMHOLTZ I enclose a letter of Dr. Cookson, 
Master of Peterhouse and Vice-Chancellor of the Uni 
versity of Cambridge, which he requested me to transmit 
to you. It is written in consequence of a suggestion I 
made to him when I saw him three days ago at Cambridge, 
that he should ask you to give the " Rede Lecture " for 
1873. I hope you will accept. You would choose your 
own subject anything upon which you would like to 
speak for an hour, or an hour and a half, to a cultivated 
audience. It is given annually in the Senate House of the 
University, and the authorities are always anxious to have 
a man of high distinction. So far as I know, no one not 
a British subject has hitherto been asked to give the lecture. 
You would probably, if you accept, prefer to have the 
lecture fully written out, and to read it to the audience. 
It is desirable that it should be afterwards published. 

In 1866 I was asked to give the "Rede Lecture." I 
accepted, and chose for my subject the " Dissipation of 
Energy." I did not succeed in getting it written out, 
and it has not been published, but I hope sometime to 
write it out (with, no doubt, many changes and additions) 
and to publish it. I hope very much you will be able 
and willing to accept. I would make a point of being 
at Cambridge at the time. Dr. Cookson will be glad to 
hear from you as soon as may be in reply. Address, 
The Rev. Dr. Cookson, Master of Peterhouse, Cambridge. 

I hope all goes well with you at Berlin. I should be 
glad to hear from you. 

I am here for a few days on telegraph business, and I go 


to-morrow to Cornwall to test a new cable which has been 
just laid from the Lizard to Bilbao. I shall be in Glasgow 
again by next Monday, I trust. I shall send you very 
soon a printed paper describing the best way I have 
found for managing the large tray battery, which has 
been doing well. I am getting a battery of eighty trays 
of larger size l than those you have, and I expect to get 
a very powerful electric light from it. Believe me, yours 
always truly, WILLIAM THOMSON. 

P.S. With trays the same size as yours, I get the 
resistance of each cell as low as -12 of an ohm. 

GLASGOW COLLEGE, Jan. 8, 1873. 

MY DEAR HELMHOLTZ We are very sorry that you 
are unable to undertake the " Rede Lecture." I cannot 
share your misgivings about success in interesting the 
audience had you been able to undertake it, but only 
regret that your engagements in Berlin make it impossible 
for you to do so. 

You have heard, no doubt, before now of the sad loss 
we have had in the death of Rankine. I send you by 
this post a copy of the Glasgow Herald (Dec. 28), con 
taining an article on his life and scientific work by Tait ; 
also a copy of the same newspaper for Dec. 26, containing 
two articles, all of which I think will interest you. We 
lost Archibald Smith, 2 too, in the same week, whose name 
you may know from the great work he has done for 
navigation in respect to correcting the compass error in 
iron ships. He was a very old and excellent friend of 
mine. He has been a hard-working Chancery barrister 
almost ever since he took his degree at Cambridge as 
"Senior Wrangler" in 1836, or else he must, with his 
great mathematical powers and inclination for physical 
science, have been one of the foremost men of science of 
this country. 

I have urged my brother, James Thomson (who is at 
present Professor of Engineering in Queen s College, Belfast,. 

1 The zincs 22 inches square. 

a [See Obituary Notice by Sir W. T., Proc. Roy. Soc. xxii., pp. i.-xxiv.] 


and has been so for many years) to apply for Rankine s 
vacant chair. I should feel much obliged by your writing 
to me a very short statement of your opinion of my 
brother s merits as a scientific investigator, or qualifica 
tions for a chair of Engineering. I have received such 
letters to-day from Andrews, Tait, and Joule, in answer 
to similar requests which I made to them. I expect one 
from Maxwell. These four, and one from you if you will 
write it to me, shall be laid before Mr. Bruce, the minister 
(" Home Secretary ") who has to make the appointment, 
and I think should constitute sufficient evidence in support 
of my brother s application. I thank you very much for 
your corrections and remarks on our Treatise. Some of 
the former we had noticed. All will be taken advantage of. 
I instructed Macmillan to send you a copy of my Electro 
statics and Magnetism^ which was published just before 
Christmas. Wishing you and Mrs. Helmholtz " a good 
new year " as we say in Scotland I remain, yours truly, 


P. S. I am hard at work just now with your 

cos \// + cr 

sin \/ + T 

and trying to help myself by it to find the shape of a 
coreless cylindrical vortex couple. 

In this winter of 1872-73 Sir William Thomson 
sent several technical communications to the newly- 
founded Society of Telegraph Engineers, of which 
he was a foundation member and vice-president. 
These were On a New Form of Joule s Tangent 
Galvanometer, On the Measurement of Electro 
static Capacity, Tests of Battery, and On a 
Tray Battery for the Siphon Recorder. This last 
invention was a form created by the necessity of 
providing a constant current for the electromagnet 



of the recorder, and consisted of a pile of lead-lined 
shallow wooden trays about a yard square containing 
zinc grids and sulphate of copper as a modification 
of Daniell s well-known type of cell. In the early 
spring he read several papers to the Edinburgh 
Royal Society, only the titles of which remain ; 
also two communications in March to the Institute 
of Engineers in Scotland, on " Signalling through 
Cables" (illustrated by a model cable) and "On 
the Rope-dynamometer." He was also very full 
of the question of distinguishing lighthouse lights 
by flashing signals, and on signalling the letters of 
the Morse code by flags and by waving lights. 
He contributed to Good Words of March 1873 an 
article on " Lighthouses of the Future" (see p. 725 

The appointment in March 1873 of Professor 
James Thomson, LL.D., to the chair of Engineer 
ing at Glasgow, as successor to Rankine, was a 
great joy to his younger brother. In the summer 
of 1873 the James Thomsons lived in Sir William s 
College house, and reported to him that the day 
after he left for Brazil his parrot, " Doctor Redtail," 
had surprised the household by saying " Sir William 
Thomson gone to Liverpool." 

GLASGOW COLLEGE, March 15, 1873. 

DEAR HELMHOLTZ I have delayed too long writing 
to thank you for your most valuable letter regarding my 
brother s qualifications for the chair of Engineering. It 
must, I am sure, have had more influence in promoting 
his appointment than almost any other document put 
into the hands of Mr. Bruce, the Home Secretary. I 

xv THE "HOOPER" 635 

have now the satisfaction of being able to tell you that 
he has been appointed to the chair. He will remain in 
Belfast to finish the business of the present session there, 
and next November will enter on his duties in Glasgow. 
I hope and fully expect that he will have much more 
time here for original research than the comparatively 
inconvenient arrangement of the " Queen s University " 
allows him in Belfast, and he will find my laboratory a 
great aid. 

I hope all goes well with you as to your new laboratory 
and school of experimental science. 

Remember me kindly to your wife, and believe me, 
yours always truly, WILLIAM THOMSON. 

[-P.^S.] I expect a visit from Joule when my brother 
comes over in the course of a week or two, to be formally 
admitted to the chair. He is President-elect of the 
British Association at the meeting appointed for Brad 
ford in Sept. next. Is there any chance of your being 
present? I am sorry that I shall not be able to be 
there as I am to be away in Brazil laying cables. 


LARGS, May 25, 1873. 

MY DEAR ANDREWS ... I ought sooner to have 
written to thank you and Mrs. Andrews for your very 
kind invitation, but I waited till I could see my way as 
to a possible time for going across to Belfast. I have 
had a great deal on hand seeing the new cable-ship 
Hooper, and sailing round in her on her first voyage from 
the builder s yard at Newcastle to Millwall Dock, etc., 
etc. I have now to get sounding apparatus, and one of 
my laboratory students indoctrinated in the use of it, 
despatched by a steamer to sail from Liverpool on the 
3 ist for Para, and take soundings along the coast of 
Brazil from Para to Pernambuco. I hope about ten days 
hence to be able to sail across, and to look after the 
setting up of an eclipsing arrangement which the Harbour 
Commissioners have ordered for the light in Holywood 
bank. If I can manage to remain a night in Belfast it 


will be a great pleasure to me to avail myself of your 
invitation, should the time, which I am sorry is still 
necessarily uncertain, be convenient to you and Mrs. 
Andrews. Believe me, yours very truly, 


On April 23 Sir William wrote to Miss Jessie 
Crum that on the Friday before he had set out on 
a three days cruise with his nephew W. Bottomley 
and Dr. James Napier. They saw the Ardrossan 
harbour light, "an excellent distinguishing light 
introduced by Mr. Thomas Stevenson." On May 
28 he wrote again from London, where the Hooper 
was taking in cable, that he was returning to 
Glasgow to sail in the yacht for Liverpool with 
Mary and Mr. Watson l to see sounding apparatus 
on a ship. 

Preparations were now far advanced for the 
laying of the new cable from Pernambuco to Para. 
He sent word to his brother : 

(Post-mark London, S.W., July 16, 1873.) 


DEAR JAMES . . . The cable-ship came out of dock 
yesterday, and after about two days here is to sail for 
Plymouth. It may be Saturday next, or more probably 
a few days later, that we leave finally for Brazil. Having 
seen the cable, and arrangements for testing all right, and 
the ship away from the factory, I leave her to-morrow 
morning, and after a day and a half in London, leave (I 
trust) to-morrow afternoon for Cowes, to sail thence west 
wards. I have a cable (the " Direct Spanish ") to test at 
Lizard before going away in the Hooper, and I hope to 
be able to sail there, and possibly further to Porthcurno, 

1 Rev. Charles Watson, D.D., who had married Miss Mary Gray Crum. 
He was Free Church minister at Largs, and died 1908. 

xv THE "HOOPER" 637 

and see trials of my new automatic sender there, and, 
still sailing in the L. R., get back to Plymouth in time. 
If wind does not answer I shall have to take train. 
Your affec te brother, W. T. 

On Friday, June 2Oth, the Hooper sailed from 
the Thames, having on board some 2500 miles of 
cable. On the 26th she landed the shore end at 
Lisbon, and proceeded westwards with the rest of 
the cable. " Here we are," wrote Jenkin to his 
wife from the Hooper, on June 29, " off Madeira at 
seven o clock in the morning. Thomson has been 
sounding with his special toy ever since half- past 
three (1087 fathoms of water)." On July 7th Sir 
William wrote to his sister-in-law from the Hooper, 
then lying in Funchal Bay, that they had been there 
a week and would be there a week more. A few 
days after leaving Plymouth a fault had been found 
in the cable in a length of 543 miles that was coiled 
in one of the three tanks ; and as the fault was 400 
miles down the coil they had had a prodigious work 
in uncoiling, splicing pieces, and recoiling. The 
expense to Hooper s Company was some ^200 per 
day ; but it was well that the stoppage had been 
here, not at Cape Verde or at Pernambuco. He 
had been struck by the marvellous beauty of the 
island. "It has been impossible," he added, "to 
keep off Darwinism, and although Madeira gave 
Darwin some of his most notable and ingenious 
illustrations and proofs (!) we find at every turn 
something to show (if anything were needed to 
show) the utter futility of his philosophy." 


An incident related by R. L. Stevenson in his 
memoir of Fleeming Jenkin, deserves mention : 

I shall not readily forget with what emotion he once 
told me an incident of their associated travels. On one of 
the mountain ledges of Madeira, Fleeming s pony bolted 
between Sir William and the precipice above ; by strange 
good fortune, and thanks to the steadiness of Sir William s 
horse, no harm was done ; but for the moment, Fleeming 
saw his friend hurled into the sea, and almost by his own 
act : it was a memory that haunted him. 

A month later Thomson wrote a further account 
of the events of the voyage : 

Aug. 8, Friday. 

We hope to be under weigh for Para, paying out cable 
from the stern of the Hooper, before dark this evening. . . . 

I have bought a parrot, green, with splendid red tips 
to his wing shoulders and end-wing feathers, dark blue 
outer wing feathers, light blue and white head, brilliant 
yellow breast. 1 The colouring is as rich and varied as 
Mrs. Bowden Fullarton s dress, and even more harmonious 
in general effect . . . 

Tell Mary that we have had a great deal of dot and 
dash practice between the Hooper and the Paraense, both 
by lamps at night and (with far more difficulty) by various 
other means in the day-time, to be ready to receive her 
soundings, and tell her where to go next in choosing out 
track for Para. We had some admirable lamp signalling 
several evenings at Funchal between the Hooper and Mr. 
Blandy s house, about i^ miles distant. The Miss 
Blandys learned " Morse " very well and quickly, and 
both sent and read long telegrams the first evening they 
tried it, to the admiration of France and other old tele 
graphers on board. 

1 This parrot, named " Professor Papagaio," lived many years in the 
College House. When he died he was stuffed, and is now in the Hunterian 
Museum in Glasgow University. 



The ladies in question were the daughters of 
Charles R. Blandy, Esq., one of the principal 
residents of Madeira, at whose villa Sir William 
was welcomed. The delay to the expedition lasted 
over a fortnight, but at last the repairs were 
completed. An eye-witness has recounted how, 
when the anchor was weighed, and the Hooper 
steamed slowly out of Funchal Bay, a figure was 
seen waving a floating streak of white drapery from 
a window of the house on the hill high above the 
port. " G-O-O-D-B-Y-E " was spelled out. " Eh ! 
What s that? What s that?" said Sir William, 
adjusting his eye-glass the better to catch the 
signals. " Good -bye, good-bye, Sir William 
Thomson." And as the ship s hull dipped beyond 
the horizon the white streak still fluttered " Good 



HOLDING his fellowship at Peterhouse, Sir William 
Thomson now frequented Cambridge more often ; 
and on returning from Pernambuco he paid a visit 
there on his way north. He wrote to his sister, 

Mrs. King : 

Oct. 22, 1873. 

MY DEAR ELIZABETH ... I am here till the 29th, 
when there is an important College meeting which I 
should have had to come back from Glasgow to attend 
if I had been there. Meantime I am very busy, having 
(in consequence of having been re-elected to a fellowship) 
accepted the office of " additional examiner " for the 
Senate-house examination of next January. Making 
questions and meeting with the other examiners and the 
moderators is my present occupation. Then in January 
there will be some days of hard work examining the 
answers. Since coming here last week I have been again 
rowing in an eight-oar (the first time since 1 846) with the 
" ancient mariners," of whom Fawcett, the (blind) member 
for Brighton, is a chief. 

David (jun 1 ") 1 has been doing very well indeed. He is 
not to go out in the Hooper this trip (to lay the Pernambuco- 
Bahia-Rio Janeiro sections, for w h she leaves the Thames 
on 3rd of Nov.), but will remain in charge at Millwall. 

1 David Thomson King, who was drowned at sea (see p. 655). 


This, I think, will be better for his progress afterwards 
than going to sea just now would have been, as it makes 
him known to Mr. Heugh and others as holding a 
responsible position. He will probably go out on the 
Para -St. Thomas (a very important part of the work) 
next spring. I shall try to get him a short holiday soon. 
I shall be in London from the 3Oth Oct. till the 3rd Nov. 
to make final arrangements and see the Hooper off. Your 
affec 6 brother, W. T. 

In December 1873 Sir William read a paper to 
the Royal Society of Edinburgh on a new method 
of determining the material and thermal diffusion 
of fluids. 

He wrote on Christmas day from Knowsley to 
Mrs. King : 

Yesterday I came here on a visit to Lord and Lady 
Derby for a few days. On Saturday or Monday I go to 
Mere Old Hall, near Knutsford, William Crum s place, to 
remain till the end of the holidays. I have to be at the 
Royal Society, Edinburgh, on Monday week to " read " a 
paper, which, however, will not, I fear, be written till after 
the reading. As Mrs. Johnstone told you, I shall have 
to be there after this winter, having been elected to be 

My Cambridge work (as one of the examiners l for the 
" Mathematical Tripos" of 1874) will keep me very busy 
till the end of January, when it will be over. I have 
brought the examination papers here (a very large heap) 
for revisal, etc. About the 2Oth of January I shall have 
to go there and remain till the list showing the result is 
given out. 

A letter to Dr. King followed : 

1 As examiner for the Mathematical Tripos Sir William Thomson intro 
duced various changes to give greater width of studies in the direction of 
Natural Philosophy. That these reforms did not please all the Cambridge 
mathematicians was natural ; but Maxwell, who had paved the way for them, 


CAMBRIDGE, /#;/. 27/74. 

I should have written sooner, if only to say so much ; 
but that I have been absolutely overwhelmed with ex 
amination papers (answers to our printed questions) for 
the " Mathematical Tripos," that is to say, the Cam 
bridge University examination for mathematical honours. 
The work is exceedingly interesting to me, but most 
laborious and wearisomely plodding. For my share of 
one sitting of the candidates I got io|- Ibs. of papers of 
written answers. I have had seven such hauls, and 
scarcely any of them less than 5 Ibs. By the same post 
with this (or by to-morrow s) I shall send a specimen of 
our printed papers of questions w h it may interest you 
to see. The questions marked with roman numerals in 
it are mine, the " arabic " by another examiner. I shall 
enclose it in a number of the Telegraphic Journal con 
taining a report of an " address " I was obliged to make 
in London on my way here. I had only (after enormous 
labour with Tatlock in two days) succeeded in getting 
enough written to occupy 4 MINUTES, and the prospect 
had made me feel as if I had a millstone round my neck 
for a fortnight before the day. So after I read the little 
beginning piece, the rest was a " leap in the dark " 
altogether. I had really not an idea of what I was going 
to say, so I was thankful when it was all over. I was sur 
prised a few days later with a copy of the Telegraphic 
Journal containing the report, which had been taken (very 
well as I thought) by a shorthand writer. It seems to 
contain every word I said, with only a few errors. . . . 

I would like very much to make a cruise in the 
Mediterranean, but next May and June I shall in all 
probability not be free to do so. 

The Society of Telegraph Engineers, destined 
later to blossom into the Institution of Electrical 
Engineers, was then not three years old. Sir 



William Thomson, as its president, in his inaugural 
address l dealt chiefly with the reflected benefits 
which science gains from its practical applications, 
and the benefit of the systems of measurement 
that grew up out of the requirements of the prac 
tical telegraphist. Terrestrial magnetism was still, 
so far as its cause was concerned, a mystery ; so 
was that of terrestrial electricity. But telegraph 
engineers, by investigating the facts over the globe, 
could help to solve these mysteries. He regarded 
the Telegraph Engineers as a society for establishing 
harmony between theory and practice in electrical 
engineering, and in electrical science generally, by 
organized co-operation. 

Within a month he gave another presidential 
address to the Glasgow Geological Society on the 
Influence of Geological Changes on the Earth s 
Rotation, and communicated a paper on Deep-sea 
Sounding. At Edinburgh he read an important 
paper on the Kinetic Theory of the Dissipation of 

On April 10 he took a preliminary cruise of 
four days on the yacht with a party including Jenkin 
and some former students. 

To Charles Abercromby Smith (now Sir Charles), 
of Cape Town, he wrote : 

GLASGOW UNIVERSITY, April 28, 1874. 

MY DEAR SMITH You know by this time that I am 
again a colleague of yours, as Fellow of Peterhouse. It 

1 See The Telegraphic Journal, vol. ii. p. 67, Jan. 15, 1874 ; Soc. of 
Telegr. Engineers Journal, iii. pp. 1-15, 1874; Pop, Lectures, ii. p. 206. 


is pleasant to be again associated with a former pupil 
and friend, though we are pretty nearly at two extremities 
of a diameter of the earth. Do you remember Tatlock ? 
at all events he remembers often hearing about you, and 
of your thermo-electric experiments in the laboratory of 
the old College. . . . This is written in his hand. As I 
have so many engagements, and so much laboratory 
work that I am kept constantly standing and walking 
about, I can seldom sit down to write anything, and 
am obliged to do nearly everything I wish in black and 
white by dictation. 

I examined for the mathematical tripos last January, 
which gave me a good deal of work from about this time 
last year till the beginning of February, first composing 
the questions, and then having all the heavy labour of 
examining the answers. I was at Cambridge in all at 
different times about five weeks, and enjoyed this very 
much, as it was very pleasant for me to live once again in 
the old College, which by the way, as you perhaps know 
too, has been greatly improved and beautified at much 
expense. . . . This will be delivered to you by Mr. Coles, 
who I believe is already known to you. He is, I believe, 
to disclose to you, and others who may be interested, a 
new form of cable which has been designed by Hooper s 
Telegraph Works Company for connecting the Cape with 
Aden and Mauritius. It is a form of cable in which I 
have great confidence. The hempen insulation is of the 
general character which both Professor Jenkin and I have 
long advocated as being the most suitable for a deep-sea 
cable, but it is a very great improvement indeed on any 
thing of this kind that we ever either designed ourselves 
or have seen designed by others. 

He was already making plans for the summer. 
On March 26 he wrote to Froude that he must be 
in London on 2Oth of April for a soiree of the Tele 
graph Engineers, and that he intended to sail from 
Falmouth on 2nd of May for Madeira. The Lalla 


Rookk was ready. He left instructions to have put 
into his Glasgow house a new heating stove to give 
next winter a heat " like Madeira," and to procure 
plants and flowers to decorate it in the autumn, and 
departed almost gaily for the trip. But this time it 
was not cable-laying that took him to Madeira. 
Soon he wrote to Mrs. King, then in Florence : 

Tuesday, May 12, 1874. 

MY DEAR ELIZABETH I believe you heard from 
Lizzie that I intended to sail from Falmouth for 
Madeira on the 2nd of May. The Lalla Rookh has done 
well taken me to the island, 1200 sea miles from Fal 
mouth, in 6f days. I anchored exactly at noon on 
Sunday in Funchal Bay, an hour before the Hooper, 
which I had left at Greenhithe on Friday week after 
testing the cable on board, and which sailed from the 
Thames on the day following. Yesterday I was answered 
Yes to a question which I asked very soon after the 
English people came out of forenoon church on Sunday. 
I was here for sixteen days last June and July on account 
of a fault in the cable. Otherwise this greatest possible 
blessing could not have come to me, that is as we see, 
but surely it is " not chance." When I came to 
Madeira in the Hooper it had never seemed to me pos 
sible that such an idea could enter my mind, or that this 
life could bring me any happiness. I thank God always 
that I was brought here. When I came away in July I 
did not think happiness possible for me, and indeed I 
had not begun even to wish for it. But I carried away 
an image and impression from which the idea came, and 
before I landed at Dover in October I had begun to 
wish for it. Hope grew stronger till yesterday, when I 
found that I had not hoped in vain. I cannot write 
more just now, but I send this because I do not wish a 
mail now on the point of leaving to go without bringing 
the good news. When you know Fanny you will be 


able to really congratulate me. Even now I think you 
will be glad for my sake. . . . Your ever affectionate 

The next letter is to Helmholtz : 

June 23, 1874. 

DEAR HELMHOLTZ I am to be married in Madeira 
to-morrow. I enclose a photograph, and I hope you will 
know the original before very long. Let me have a line 
addressed Athenaeum Club, London, to say if you are to 
be at the British Association in Belfast. I do not intend 
to be at the meeting, but if you are to be there we might 
see you on your way to or from it. We think of sailing 
from Madeira in the Lalla Rookh about the middle of 
July, but have not made up our minds whether to make 
as short a passage as we can to England, or to touch at 
Gibraltar, Lisbon, Vigo, Corunna, on our way, or to keep a 
more westerly course and make a little cruise among the 
Azores. The future mistress of the Lalla Rookh promises 
to be a very good sailor, having already been out a good 
many times for a day s sail, one of them round the 
Desertas (about 70 miles) and always hitherto escaped 
sea-sickness. Still it remains to be seen whether a yacht 
cruise on the open Atlantic is a pleasure in direct or in 
inverse proportion to its duration. 

My present happiness is due to a fault in the cable 
which kept the Hooper for sixteen days in Funchal Bay 
last summer. I hope you and Mrs. Helmholtz and your 
children are all well. With kind regards, I remain, yours 
always truly, WILLIAM THOMSON. 

He wrote the same day a similar letter to Dr. 
J. Hall Gladstone, adding a congratulation on his 
election to the Fullerian Professorship of Chemistry 
at the Royal Institution : " To be Faraday s suc 
cessor is indeed an honour. I am sure you will 
find the post most congenial to you." 


The Glasgow Herald of July 4, 1874, contained 
the following announcement : 


At the British Consular Chapel, Funchal, Madeira, 
on the 24th ult., Sir WILLIAM THOMSON, Professor 
of Natural Philosophy in the University of Glasgow, 
Esq., of Madeira. 

To his sister Sir William wrote : 

ST. ANNA, MADEIRA,/*/// 5, 1874. 

On the 24 th we rode away in the afternoon to a place 
called St. Antonio de Serra, about 4 miles ride from 
Funchal, and 2000 feet above the sea level. We lived 
there in a house belonging to an uncle of Fanny s for a 
few days and then came across to this place. We have 
been taking rides and walks every day and enjoying to 
the utmost the beauties of Madeira. On Thursday next 
we return to Funchal, and remain about 10 days in Mr. 
Blandy s house before sailing away in the Lalla Rookh. 
-Your affe c brother, W. T. 

The homeward voyage in the yacht was 
shortened, for off Finisterre she broke her main 
gaff, and finished the voyage under top-sail to 
Cowes for repairs. Sir William and Lady Thom 
son paid a hurried visit to London, returning to 
Cowes for further cruising between engagements 
in town, which prevented them from going to 
the British Association at Belfast. Here James 
Thomson was to be president of the Engineering 
section, and to him, on August 1 2, Sir William wrote, 
from the Great Western Hotel, Paddington : 



We left Cowes on Friday to come here on business. 
I have been overwhelmed with arrears of correspondence 
reports of recent expeditions. The Hooper is expected 
home about the 1 8th, and I must be here for some time 
after that to decide what is to be done with the defective 
cable which the Hooper brings home (which was to have 
been laid between Cayenne and Demerara, but is brought 
back because defective). I don t know how long this 
may keep me, but it may be that for several weeks yet I 
must be within call of London. We return to the Lalla 
Rookh at Cowes to-morrow to remain " at home " in her 
until we return to London for the Hooper. . . . 

W. Bottomley tells me you are going to refer to the 
eclipsing system of distinguishing lighthouses. I trust 
the one on Holywood Bank will be in action and giving 
practical proof of the plan. You can scarcely be too 
strong in expressions, as the NEED for distinction in REAL 
experience, though sailors and admiralty officials believing 
honestly that they speak from experience are quite ready 
to deny it. 

I think you might refer to the soundings by pianoforte 
wire. . . . 

When we get quite free from London we shall prob 
ably sail for the Clyde, weather and time permitting. We 
should touch at several places on the way so as to have 
chiefly sailing by day and resting in port by night. If 
the Holywood Bank eclipsing light is as I hope it will 
be, we should probably go into Belfast Lough to look 
at it on our way, and even without that inducement 
we might make Belfast one of our ports and take a few 
hours to run up and see our friends there. You, I 
suppose, will be back in Glasgow before that time ; but 
when we get back to the Clyde I hope you will be able 
to come and have a few days sailing with us. We shall 
take the earliest opportunity after getting to Scotland to 
go to the College, and perhaps remain there a few days ; 
but the yacht will be our headquarters probably till about 


the middle of October. You must take some thorough 
rest after you get over the B.A. and your address. I am 
afraid in the meantime you will be too busy to allow you 
much rest. . . . Your affectionate brother, 


They were not able to attend the British 
Association, but Sir William communicated two 
papers : one on Perturbations of the Compass at 
Sea, and another on his Improvements in Compasses. 
To Dr. King he sent a message strongly disap 
proving of Tyndall s famous presidential address, 
and of the dictum in which he had discerned in 
matter " the promise and potency of all terrestrial 
life." Thomson thought it " especially inappro 
priate." Later they sailed to Belfast, thence to 
Largs to visit friends and relations ; then went to 
Glasgow to see "home." After that there was a 
final cruise to Arran before the session began. 

On October 29th Sir William wrote to Mrs. 
King : 

We have bought a little piece of ground, Kirklands, 
Largs, bounded on the south and north-west by the Noddle 
Burn (Noddsdale Burn, properly), on the road to Barr s 
farm, to build a house on. We shall begin building 
before very long, I hope. I thought you would be 
interested to have the earliest news of this. 

" Netherhall " was the name given to the house, 1 
a commodious country mansion in the Scottish 
baronial style, the building of which occupied many 
months. Sir William, with the aid of his brother, 

1 For a full description of the building, see The Building News, June 27,. 
1890. It is there stated that the cost was 12,000. 



took a large part in the planning of the building, 
which was original in many ways. He himself 
engaged a master-mason and a master-carpenter, 
instead of letting the contract to a builder a costly 
and vexatious plan in the sequel. A dozen years 
later the estate was much improved by the purchase 
of additional ground. Netherhall was the scene in 
after years of many family reunions, and of extended 
hospitalities presided over by the gracious hostess. 
It was here that Sir William sought quiet hours 
when the yachting days were over ; and to it he 
retired when he withdrew from his chair in 1899. 

Sir William Thomson was now 51 years of 
age, but, save for his slight lameness, as active as 
in youth. For nearly thirty years he had never 
felt the want of money, and for some years past 
had enjoyed a very large professional income. 1 He 
was supremely happy in his domestic life. Lady 
Thomson had been welcomed into the circle of 
family relations, and directed his household with 
rare dignity and grace. His academic duties were 
lightened by the devoted assiduity of his official 
assistant MacFarlane, and of his demonstrator and 
deputy-lecturer, James T. Bottomley. 

A graphic picture of Sir William as he appeared 

1 The income of the partnership of Thomson, Varley, and Jenkin was 
considerable, for they derived handsome profits from their inventions. Varley s 
patent for the signalling condenser was very profitable. Sir William, writing 
to Jenkin in 1881, speaks of "the quadrant electrometer, the mirror galvano 
meter, and the last recorder patent, which is now bringing us ^3000 from the 
Eastern Telegraph Co., .2100 from the Eastern Extension, and ,1500 
from the Anglo." The partnership of Thomson and Jenkin as consulting 
engineers to various cable companies was also extremely profitable, and 
brought them each several thousands a year. 


to his students has been recorded by Professor 
Andrew Gray, then one of the merry students who 
filled the ten benches of the lecture theatre, after 
wards his trusted secretary and scientific assistant, 
and finally his successor in the chair of Natural 
Philosophy. By his kind permission * the following 
extracts are given from his admirable book : 

The writer will never forget the lecture-room when he first 
beheld it, from his place on Bench VIIL, a few days after the 
beginning of session 1874-75. Sir William Thomson, with 
activity emphasised rather than otherwise by his lameness, came 
in with the students, passed behind the table, and, putting up 
his eye-glass, surveyed the apparatus set out. Then, as the 
students poured in, an increasing stream, the alarm weight was 
released by the bell-ringer, and fell slowly some four or five feet 
from the top of the clock to a platform below. By the time the 
weight had descended the students were in their places, and 
then, as Thomson advanced to the table, all rose to their feet, 
and he recited the third Collect from the Morning Service of the 
Church of England. It was the custom then, and it is still one 
better honoured in the observance than in the breach (which 
has become rather common), to open all the first and second 
classes of the day with prayer ; and the selection of the prayers 
was left to the discretion of the professors. Next came the roll- 
call by the assistant ; each name was called in its English or 
Scottish (for the clans were always well represented) form, and 
the answer " adsum " was returned. 

The vivacity and enthusiasm of the Professor at that time was 
very great. The animation of his countenance as he looked at 
a gyrostat spinning, standing on a knife-edge or on a glass plate 
in front of him, and leaning over so that its centre of gravity 
was on one side of the point of support ; the delight with which 
he showed that hurrying of the precessional motion caused the 
gyrostat to rise, and retarding the precessional motion caused the 
gyrostat to fall, so that the freedom to " precess " was the secret 
of its not falling ; the immediate application of the study of the 
gyrostat to the explanation of the precession of the equinoxes, 
and illustration by a model of a terrestrial globe, arranged so 

1 English Men of Science. Lord Kelvin, an Account of his Scientific Life 
and Work. By Andrew Gray, LL.D., F.R.S., V.-P.R.S.E. London, J. M. 
Dent and Co., 1908. 


that the centre should be a fixed point, while its axis a material 
spike of brass rolled round a horizontal circle, the centre of 
which represented the pole of the ecliptic, and the diameter of 
which subtended an angle at the centre of the globe of twice the 
obliquity of the ecliptic ; the pleasure with which he pointed to 
the motion of the equinoctial points along a circle surrounding 
the globe on a level with its centre, and representing the plane 
of the ecliptic, and the smile with which he announced, when 
the axis had rolled once round the circle, that 26,000 years had 
elapsed all these delighted his hearers, and made the lecture 

Then the gyrostat, mounted with its axis vertical on trunnions 
on a level with the fly-wheel, and resting on a wooden frame 
carried about by the Professor ! The delight of the students 
with the quiescence of the gyrostat when the frame, gyrostat and 
all, was carried round in the direction of the spin of the fly 
wheel, and its sudden turning upside down when the frame was 
carried round the other way, was extreme, and when he suggested 
that a gyrostat might be concealed on a tray of glasses carried 
by a waiter their appreciation of what would happen was shown 
by laughter and a tumult of applause. 

On one occasion, after working out part of a calculation on 
the long fixed blackboard on the wall behind the table, his chalk 
gave out, and he dropped his hand down to the long ledge which 
projected from the bottom of the board to find another piece. 
None was there, and he had to walk a step or two to obtain 
one. So he enjoined MacFarlane, his assistant, who was always 
in attendance, to have a sufficient number of pieces on the ledge 
in future to enable him to find one handy wherever he might 
need it. MacFarlane forgot the injunction, or could not obtain 
more chalk at the time, and the same thing happened the next 
day. So the command was issued, " MacFarlane, I told you to 
get plenty of chalk, and you haven t done it. Now have a 
hundred pieces of chalk on this ledge to-morrow ; remember, a 
hundred pieces ; I will count them ! " MacFarlane, afraid to be 
caught napping again, sent that afternoon for several boxes of 
chalk, and carefully laid the new, shining, white sticks on the 
shelf, all neatly parallel, at an angle to the edge. The shelf 
was about sixteen feet long, so that there was one piece of chalk 
for every two inches, and the effect was very fine. The class 
the next morning was delighted, and very appreciative of Mac- 
Farlane s diligence. Thomson came in, put up his eye-glass, 
looked at the display, smiled sweetly, and turning to the applaud 
ing students, began his lecture. 

In the higher mathematical class, to which he lectured on 


Wednesdays at noon, Thomson was exceedingly interesting. 
There he seemed to work at the subject as he lectured ; new 
points to be investigated continually presented themselves, and 
the students were encouraged to work them out in the week- 
long intervals between his lectures. Always the physical inter 
pretation of results was aimed at ; even intermediate steps were 
discussed. Thus the meaning of the mathematical processes 
was ever kept in view, and the men who could follow were made 
to think while they worked, and to regard the mathematical 
analysis as merely an aid, not an end in itself. " A little ex 
penditure of chalk is a saving of brains," "the art of reading 
mathematical books is judicious skipping," were remarks he 
sometimes made, and illustrated his view of the relative import 
ance of mathematical work when he regarded it as the handmaid 
of the physical thinker. 

The closing lecture of the ordinary course was usually on light, 
and the subject which was generally the last to be taken up for as 
the days lengthened in spring it was possible sometimes to obtain 
sunlight for the experiments was often relegated to the last 
day or two of the session. So after an hour s lecture Thomson 
would say, " As this is the last day of the session I will go on 
for a little longer after those who have to leave have gone to 
their classes." Then he would resume after ten o clock, and go 
on to eleven, when another opportunity would be given for 
students to leave, and the lecture would be again resumed. 
Messengers would be sent from his house, where he was wanted 
for business of different sorts, to find out what had become of 
him, and the answer brought would be, hour after hour, " He is 
still lecturing." At last he would conclude about one o clock, 
and gently thank the small and devoted band who had remained 
to the end for their kind and prolonged attention. 

In the course of his lectures Thomson continually called on 
his assistants for data of all kinds. In the busiest time of his 
life the fifteen years from 1870 to 1885 -he trusted to his 
assistants for the preparation of his class illustrations, and it was 
sometimes a little difficult to anticipate his wishes, for without 
careful rehearsal it is almost impossible to make sure that in an 
experimental lecture everything will go without a hitch. The 
digressions, generally most interesting and instructive, in which 
he frequently indulged, almost always rendered it necessary to 
bring some experiment before the class which had not been 
anticipated, and all sorts of things were kept in readiness lest 
they should be wanted suddenly. 


He wrote shortly to Prof. Andrews : 

DEAR ANDREWS We are now settled here for the 
session. At your convenience I shall be glad to have the 
thermoelectric battery and the magnet to test them. . . . 
Is my compression apparatus ready ? I shall be very 
glad indeed to have it when it is so, and greatly obliged 
to you for the trouble you have so kindly taken for me 
about it. We said good-bye with much regret to the 
Lalla Rookh on Friday last, and left her to be laid up for 
the winter in the Gareloch. After a succession of severe 
gales, in one of which (the very violent one that wrecked 
the Chusan at Ardrossan) she dragged both anchors, and 
went ashore in the Gareloch, we had a week of fine 
weather and a little beautiful sailing to Arran and in the 
Firth of Clyde. So we were very sorry to leave her. We 
were fortunately not on board the night of her shipwreck, 
by a mere chance of an unexpected meeting of the " Uni 
versity Court " keeping us in Glasgow. She was got off 
without damage and by ourselves without assistance or 
expense, after being 36 hours on soft sand in a very good 

This autumn and winter he had much corre 
spondence with Dr. John Hopkinson about electro 
lytic action, contact electrification, and the residual 
charges of Leyden jars, which the latter was 
investigating in connection with the composition 
and optical properties of glass. 

Then came terrible news. The La Plata, a ship 
chartered by Siemens Brothers to carry some 250 
miles of cable to South America for the Western 
and Brazilian Telegraph Company, had foundered 
off Ushant on Nov. 29th. Amongst the sixty lives 


lost was that of young David Thomson King, Sir 
William s nephew, one of the skilled electricians of 
the expedition, a man of great promise. To Mrs. 
King, then in Rome, Sir William wrote : 

David did his duty nobly to the last. Of that I think 
you might be sure, even if we had known nothing but that 
there had been a disaster. One of the survivors told Willie 
Bottomley that he had seen him very near the end, hard 
at work passing coals along the deck. . . . The news of 
what happened so soon after receiving cheery letters from 
him has been a terrible shock to us all. The unspeakable 
grief it will be to you and David, and to young David s 
brother and sisters, is in all our minds. God only can 
mitigate it to you, and to Him we pray that it may be 
mitigated. I cannot write more now. I need not tell you 
that I share your grief, and we have the warmest sympathy 
of my dear wife. 

Sir William and Lady Thomson spent Christmas 
at Knowsley and then went to William Crum s 
house near Knutsford. At the New Year they went 
to Edinburgh, where Sir William was to read papers 
on two new instruments, a tide-calculating machine 
and a tide-gauge, and on some curious phenomena 
of capillary attraction which he had lately found out. 

A project for enlarging Owens College, Man 
chester, was then being discussed, and some objec 
tion being taken to the expansion of its chemical 
and other laboratories as a degeneration from the 
legitimate work of a University, Thomson wrote 
to The Times (of Jan. 20, 1875) a remonstrance: 

If to give experimental science and chymistry their 
proper position in the curriculum, and to found new 
professorships and provide them with all the apparatus 


for complete and successful study, are tests of degeneration, 
Oxford, and Cambridge headed by its Chancellor, and all 
the Scotch Universities, have been labouring strenuously 
for many years to earn this reproach. . . . Surely a uni 
versity must be an emporium of knowledge. . . . Owens 
College does, as far as its means allow it, perform the 
true functions of a University, the cultivation and the 
teaching to all comers of the whole body of human know 
ledge. It has become what it is by a true process of 
natural selection. It now wants, and it deserves, national 
funds, supplementary private munificence, and a charter 
constituting it a National University. 

Principal Greenwood, Professors Ward and 
Balfour Stewart, and Professor (now Sir Henry) 
Roscoe, wrote thanking him for his generous 
recognition of their case. The matter dragged on 
for many months. 

His reply to Roscoe was : 

April 26, 1876. 

MY DEAR ROSCOE Ever since receiving your letter 
with papers regarding Owens College, which I read with 
much interest and satisfaction, I have been in a very 
aggravated condition of high pressure accumulating as 
usual till the final blow-off at the end of the session now 
taking place. This has prevented me from sooner writing 
to you to express my most cordial approval of the pro 
posal to now move energetically in promoting the earliest 
possible creation of the University of Manchester. The 
work already done and the position already taken by 
Owens College seems to me to make a University of 
Manchester inevitable. I utterly differ from those who 
object to any moderate multiplication of universities 
throughout the British dominions such as we have in Scot 
land, and I believe it will be a very great benefit indeed in 
England if you succeed, as I hope you will, and that very 
soon, in obtaining a charter constituting Owens College 


into a national University. With best wishes for your 
success, I remain, yours truly, WILLIAM THOMSON. 

Two years later, a word from Sir William 
Thomson again revived the project, as narrated in 
The Life and Experiences of Sir H. E. Roscoe, 
pp. 175-176. 

The fame of the Manchester Penny Science Lectures 
for the People reached what the Scots term " the second 
city of the Empire," and I was invited to give the opening 
lecture of a similar series, which a committee in Glasgow 
had established. My lecture, on " The Chemical Action 
of Light," was given in 1878, in the large St. Andrew s 
Hall, before a crowded audience. After it was over Sir 
William Thomson (Lord Kelvin), who had presided at the 
lecture, remarked to me, " Why do not you make Owens 
College into a University ? " I said that we had often 
talked about it, but that we thought the time had not yet 
arrived for so momentous a proposal. He replied : "You 
are quite mistaken. The time has arrived ; you have 
quite attained a University position, and you ought to 
make it the University of Manchester." Thinking the 
matter over, I came to the conclusion that he was right, 
and on returning home consulted my friend Dr. Ward, 
now Master of Peterhouse, who was then our Professor of 
History, on the subject. He at once fell in with the 
suggestion, and after some time we convinced our Principal, 
Dr. Greenwood, who was of a cautious disposition, that 
we ought to make the attempt to found a new English 

On Feb. 3rd, 1875, Sir William delivered in 
the City Hall, Glasgow, a lecture to about 2000 
persons on " The Tides." Only a small part of this 1 
was written out ; and the reports of it are brief. 

1 See Popular Lectures, vol. iii. pp. 191-201; also see The Engineer > 
Feb. 19, 1875. 


Of the activities of this period, and of the 
demands upon Thomson s time, some idea may 
be formed from the following letter to James 
Napier : 

Feby. 16, 75- 

DEAR NAPIER The new method in my paper does 
take into account the fact of the centre of gravity not 
being in a vertical with the point of support, and the 
effect of this fact on the heeling error. Indeed, what I 
have called the heeling error is simply the effect of that 
fact. If you please I would explain it in the physical 
section of the Philosophical Society in the most unpopular 
manner you wish. I can also, if you please, with great 
ease, do the same for the tides, and shall be glad to do 
so if desired, but on this condition, that not a single scrap 
in black and white is expected from me for the Proceed 
ings. I am now three years deep in unfulfilled pledges 
for the Geological and Philosophical Societies, and I have 
resolved to stop payment and put up shutters in my 
factory of papers for the Proceedings of either Society. 
Bringing apparatus and giving an explanation of it at the 
Society, or explaining theoretical subjects mathematically 
or non-mathematically, I shall be glad to do at any time 
provided I am not expected either to look at a report 
of it taken by any one else, or to give anything in black 
and white myself for publication. Every moment of time 
henceforth that I can give to writing for publication must 
be devoted to T & T , and to the description of physical 
experiments bringing out new properties of matter, of 
which I have now a good many on hand, for the Royal 
Society of London. 

In these months Sir William had much corre 
spondence about Lighthouses with Dr. Hopkinson. 
On the same topic also, he wrote to Prof. Peirce of 
Harvard : 


Ap. 22, 1875. 

DEAR PROF. PEIRCE I send you by book packet 
along with this two articles on deep-sea sounding by 
pianoforte wires. You will see that I have been obliged 
to contrast our own Admiralty not very favourably with 
yours in respect to liberality towards suggestions for im 
provement. Our authorities are indeed exceedingly heavy 
to move in any way which involves the introduction of 
new ideas. I am not allowing suggestions for distinction 
of lighthouses by groups of eclipses of short and long, 
according to the Morse system, to fall asleep. A light 
house on this plan has been in action on Holywood Bank, 
Belfast Lough, since the first of November, and I am told 
by the harbour authorities that captains, pilots, and sailors 
are all much pleased with it. They know it with perfect 
confidence from any other light afloat or ashore. It was 
till last November a red fixed light which could only be 
seen about two miles off, and was constantly liable to be 
mistaken for a ship s port-side light. When my eclipsing 
machine was applied to it the red shade was removed, 
and in all respects the light was left unchanged. Besides 
having the advantage of being unmistakable for anything 
else, it is now visible for a distance of five miles. Its 

distinguishing mark is the Morse letter U (dot 

dot dash). The duration of the dot eclipse is half a 
second, the duration of the dash is three times as long. 
But I keep in the background the fact that, adhering 
simply to the letters of the Morse alphabet, we can with 
the greatest ease give twenty -eight distinctions, each 
thoroughly unmistakable for any other. This has a 
tendency to frighten " practical " men. I therefore to 
some " practical " men scarcely venture to call the dis 
tinguishing mark which I would propose for any one 
light a " letter," and rather say " You will know that is 
Sanchoty Head, a short and a long," and have it printed 
in the list of lights ; and again " You will know that is 
Gay Head, a long and a short" Nobody can but answer 
" Yes " to this question. The moment you see a short 
and a long you know that it is not Gay Head, but 


Sanchoty Head, or in the case of two lighthouses not 
very far from one another it may be judged expedient to 
have one of them marked by different numbers of eclipses. 
The Sanchoty Head, for instance, might be the letter E 
(one short eclipse of half a second occurring every ten 
seconds, or every five seconds, as may be judged ex 

Then the Gay Head might be the letter U ( ), or 

the letter D ( ), or the letter R ( ). (You may 

tell them that a short and a long is the letter N if you 
please ; but I am told that it would perplex " practical " 
men to tell them so much : I don t believe it, because I 
don t find sailors more apt to be confused than landsmen 
by anything in reason. Still, as long as I speak to Light 
house Boards and their secretaries and engineers I am 
quite ready to say nothing about the Morse alphabet, but 
when I get to sea I do not find that a sailor is at all 
more apt to mistake the Holywood light for anything else 
when I tell him " that mark means the letter U " ). 

Is there any hope that your Lighthouse Board would 
give the eclipsing system a trial ? For three years back 
I have continually pressed it on our Hydrographic Office, 
but I have had even more cold water thrown on this 
proposal than on the pianoforte wire sounding. I should 
not be at all sorry for either them or the Elder Brethren 
if the United States authorities were to anticipate them 
in this matter as they have in the sounding by pianoforte 
wire. I have had two years struggle with the compass 
department of our Hydrographic Office to induce them to 
take up some suggestions I have brought before them for 
the correction of the compass in iron ships. They are 
most obliging in giving me information, but are utterly 
immovable for anything like co-operation for anything 
new, as they were in the matter of sounding by pianoforte 
wire. I now see that if anything is to be done in the 
matter the whole business of it will fall upon myself, and 
I have therefore resolved to take out a patent for a new 
form of compensator and appliances which I have now 
made. I doubt whether with all the obligingness that has 


been shown to me I should be more successful in getting 
a trial of it than I have been in getting a trial of the 
pianoforte wire by our people, until I can offer it to them 
as a patented invention. I enclose a small paper by which 
if you glance at the conclusion you will see that my great 
need is small needles. I have now a compass on my 
table before me with four needles, of which the longest 
are each two inches long. In the course of this summer 
I hope to get a thorough trial of it at sea with the 
appliances which I have designed for determining the 
error due to the ship s magnetism. In the course of 
the last two or three days it has helped me to a very 
startling discovery regarding the correction of the quad- 
rantal error by soft iron correctors as hitherto practised. 
The best thing hitherto done in this way undoubtedly is 
the iron cylinders of the Liverpool Compass Committee 
applied to our Admiralty standard compass. The results 
are described in page 174 of the second volume of your 
reprint of papers on the magnetism of ships and the 
deviation of the compass. There I find the maximum 
deviation produced by a pair of the 1 2-inch cylinders 
with their ends 7 inches from the centre of the compass 
card stated to be 12 50 . Now I find by experiment 
that considerably more than one-half of this error is due 
to magnetization induced in the corrector by the needles 
of the compass! Hence if the 1 2-inch cylinders were 
applied at Liverpool to correct a quadrantal deviation of 
maximum value 12 50 , the error would be enormously 
over-corrected in the same ship in the Gulf of St. Lawrence, 
and very much under-corrected at the equator. An in 
finitesimal needle placed at the position of the centre of 
the Admiralty compass card in those trials would have 
shown about 5 of effect only instead of 12 50 . I am 
experimenting just now to find as exactly as need be the 
amount, but I have already seen that it is certainly less 
than one-half that found in the reported trials. I intend 
to send a short communication to the Royal Society on 
this subject, and hope to have the pleasure of sending 
you a copy when I get it in print. 


In April he read a paper to the London Mathe 
matical Society, and gave a discourse to the Royal 
Institution on Tides ; also three papers to the 
Edinburgh Royal Society, one on the Theory of the 
Spinning Top, one on the Vibrations of a Stretched 
String of Gyrostats, and a third (in collaboration 
with Dr. John Perry) on the Capillary Surface of 
Revolution. In June he communicated to the Royal 
Society two memoirs, one on the Effects of Stress 
on Magnetization, the other on Electrolytic Con 
duction in Hot Glass. 

The loss of the Schiller on the Scilly Isles in 
May gave Sir William Thomson occasion to address 
to The Times of May i2th a remonstrance on the 
neglect to provide means for taking rapid soundings 
which would have enabled the ship to keep outside 
the 50 fathom line. He was then at Peterhouse. 

The summer was filled up with cruises on the 
yacht at Cowes and other places ; and in August he 
and Lady Thomson went to Bristol for the meet 
ing of the British Association. Here he read no 
fewer than seven papers, three of them mathemati 
cal, two on Tides and his Tide-calculating Machine, 
one on Magnetism, and one on Lighthouses. 

At the concluding meeting Sir William Thomson 
moved a vote of thanks to the President, Sir John 
Hawkshaw, in the following terms : 

In him they found none of the Mephistophelian 
cynicism which said : 

Grau, theurer Freund, ist alle Theorie, 
Und griin des Lebens goldner Baum, 


For Sir John Hawkshaw the golden tree of life retained 
its greenness in the revivifying influence of true theory. 
Whoever heard him describe the tunnel which is to 
connect England with France could not but have felt, 
even in such a result as that, that they had a work of 
the greatest possible interest for human beings, irrespective 
of all scientific questions a result which would give them 
a different feeling from any which they could now have 
towards their neighbours. He wished their president 
success in that undertaking, and hoped in a few years 
they would see it finished. 

On Sept. 2 he attended at Bristol a meeting 
called in support of the foundation in that city of 
a University College. To this project he accorded 
the warmest welcome, and expressed the hope that 
any of them living twenty-five years hence might 
see it grown into a fully-organized University. 

From Bristol Sir William and Lady Thomson 
went to visit the Duke of Argyll at Inveraray, where 
Royalty was being entertained. The memoirs of 
the Rev. Principal Story, who was also a guest, 
record the following incident : 

Sept. 27. The Thomsons dined this evening, and in 
the saloon, soon after the Queen came in, Princess Louise, 
in handing her something, upset a flower-glass and spilt 
the water, which simple incident sent H.M. into fits of 
laughter, which seemed increased by the spectacle of Sir 
William Thomson, in an access of loyalty, wiping up the 
water with his pocket-handkerchief and then squeezing it 
into his tea-cup. The Queen smiled over it till she went 
away. Solvuntur risu. 

On Nov. ii Thomson gave, in the Glasgow 
City Hall, a public lecture on Navigation, referred 


to on p. 719 below. On the walls were hung two 
great charts reproduced on pages 97 and 385 of 
his Popular Lectures, vol. iii. of his voyage in 
the Lalla Rookk to and from Madeira in 1874, 
marked with observations and soundings. When 
he referred to these as taken during the sailing of 
"a certain ship," on a certain eventful voyage two 
years ago, the audience recognising the allusion 
cheered enthusiastically. 

In December he dealt with vortex statics at the 
Royal Society of Edinburgh. He wrote to Hop- 
kinson on his Leyden jar experiments. 

Dec. 13, 1875. 

DEAR HOPKINSON A long time ago, in the old 
University buildings, I made just such experiments on 
alternate positive and negative return charges. I used to 
keep a jar charged positively for several hours, sometimes 
for several days, then negative for several minutes or 
several hours, then positive again for a shorter time and 
so on, lastly discharge and put to electrom r . I always 
got alternate positive and negative return charges, but I 
forgot how many alternations I succeeded in getting. I 
never published the result, but I might have properly 
done so, and I think you should publish yours. I spoke 
of them to a good many people (Maxwell, probably 
enough, among them), and showed them in my class. I 
think, probably, similar observations must have been made 
last century, and I daresay a hunt into old books and 
journals might find something of them, but I have never 
seen them mentioned in print, and I don t believe they 
are generally known. 

You will certainly, I think, get the result however 
infinitesimal you make the capacity of the non-coated 
part. I shall be glad to send to the R. S. a statement 


of your results if you please. It would be perfectly well 
suited for the Proceedings. People always seem to see 
it by common sense. If there can be a return charge 
at all there must be the possibility of alternately positive 
and negative return charges. (If one note can soak out 
of Baron Munchausen s post-horn, why not the whole tune 
only it ought to have come out backwards !) 

The existence of return charge, of course, disproves 
the simple exponential formula Ae~ A/< , but it will be curious 
to find if your experimental series is better than any 
other obvious empirical formula. Yours very truly, 


The year 1876 was one of astonishing activity. 
During the spring Thomson made several com 
munications to the Royal Society of Edinburgh 
on Vortex Columns, on an Application of James 
Thomson s Integrator to Harmonic Analysis, on 
Vortex Theory of Gases, and on Thermodynamic 
Motivity. To the Royal Society of London he 
gave three papers on Mechanical Integration. The 
physical laboratory was in full swing, with new ex 
periments on the secular diffusion of liquids, and 
new forms of gyrostats. He was also actively cor 
responding with Stokes and other scientific friends, 
as the following letters show : 



We are all greatly delighted in my laboratory with 
what you have given us my old assistant MacFarlane is 
in raptures to see carbonic acid compressed to the liquid 
state in that always ready way. It will be a splendid 
lesson to my students, and I feel that henceforth they 


will every session know more of the meaning of liquids 
and gases and vapours than I have ever been able to 
teach them before. 

I was not able before I left Glasgow to get the warm 
ing apparatus applied, but you may be sure that we shall 
not wait patiently long, before doing this and going 
through the continuity cycle. 

I need not attempt to tell you how much I thank you 
and how grateful I feel for all the trouble you have taken, 
and how much I value the result. When I see it set up 
in my apparatus room I think of it as a monument 
which will remain to generation after generation of pro 
fessors and students of Natural Philosophy in the Uni 
versity of Glasgow long after I am gone, and will still be 
valuable and I hope valued as now. Believe me, yours 
always, W. THOMSON. 

On Jan. 21 he wrote to Hopkinson on a form of 
pendulum suspension, and asked him to come to 
stay with him, as on Feb. 16 Huxley was coming 
to Glasgow to lecture, and on 23rd Aitken was to 
show experiments on the rigidity of a running 
chain. He wrote again to Andrews : 

March n, 1876. 

DEAR ANDREWS I thank you very much for your 
warm congratulations on the Matteucci prize. To have 
such congratulations from you and other friends adds 
greatly to the gratification which such a reward for 
scientific work brings. ... I have been very much 
engrossed with the compass and sounding machine, but 
still trying to get something done in the laboratory. We 
have begun to get some very fine results as to the effect 
of transverse pull on magnetization by applying and 
removing hydraulic pressure on the interior of a gun 
barrel under the influence of longitudinal magnetizing 
force. We find opposite effects to those of longitudinal 


pull, and as in the case of longi 1 pull a certain degree 
of magnetizing force for which the effect of pull is zero 
with contrary effects for weaker and stronger magnetizing 

March 17/76. 

MY DEAR ANDREWS I hope you will accept the 
presidentship, 1 and that you and Mrs. Andrews will take 
up your quarters here with us for the meeting. It will 
be a great pleasure to us, and as all the sections meet in 
the University buildings, I think you will find it more 
convenient and less fatiguing than living at any greater 
distance could be. So you must make up your mind to 
come to us. We hope to have the Taits and the Crum 
Browns also with us. . . . 

I have to-day been seeing an exquisite electric experi 
ment, quite a first-rate discovery, by Dr. John Kerr. You 
may have seen it in the Phil. Mag. a few months ago. 
It is literally an " illumination of Faraday s lines offeree." 
A very moderate tension (by a small electric machine) 
much inferior to that required to produce a spark, 
between two wires about ^-inch apart, in bisulphide of 
carbon, instantly brightened the flame of a lamp which 
had been extinguished by Nicol s prisms, and the light 
disappeared again the instant the electric tension was 
reduced to zero (by touching the prime conductor). The 
effect was the same as that produced when a piece of 
glass was substituted for the liquid and pulled in the 
direction which had been that of the electric force, by 
holding a broad slip of window glass in the course of the 
light between the Nicol s prisms, with the bisulphide also 
in the course. The electric effect was annulled by bend 
ing the glass by a moderate force with one s fingers, and 
holding it so that the light passed through the condensed 
part. When held so that the light passed through 
the dilated part of the glass the luminous result 
of the electric force was augmented. I bespoke an 

1 Of the British Association to be held in Glasgow that year. 


exhibition of the experiments for the Association. Kerr 
lives in Glasgow (Principal of the Free Church Normal 
School) and is continuing his investigations. No doubt 
he will have new results to show when the time of the 
meeting comes. He was a pupil of mine for the first two 
or three years of my professorship, now thirty years ago. 

A Special Loan Collection of Scientific Apparatus 
was exhibited in the spring of 1876 at South 
Kensington ; and to this Thomson contributed a 
remarkable show of instruments, electrometers, 
galvanometers, compasses, the Tide-predicter, and 
an array of miscellaneous instruments of precision. 
Conferences, too, were arranged at which lectures 
were given by eminent men. The remarkable 
series of Thomson s electrometers was described in 
two lectures by James T. Bottomley ; while Sir 
William himself gave, on May 17, a discourse on 
Electrical Measurement, which is reprinted in his 
Popular Lectures, vol. i. pp. 423-454. 

To celebrate the centenary of the Independence 
of the United States the American Government 
organized the Centennial International Exhibition 
of 1876 at Philadelphia. Sir William Thomson was 
invited to act as one of the judges in Group 25, 
comprising instruments of precision, research, ex 
periment, and illustration, including telegraphy. 
He left Glasgow on May 20, and wrote to Helm- 
holtz from New York : 

S.S. ftt/sssA arriving NEW YORK, 
May 30/76. 

MY DEAR HELMHOLTZ Just before leaving England 
I heard with pleasure that you and Mrs. Helmholtz are 


coming to the meeting of the British Association in 
Glasgow next September, and in the hurry of coming 
away I was unable to write to you and ask you to stay 
with us in the University. I now do so to catch the 
mail steamer which leaves New York to-morrow. 

My wife bids me say that she looks forward with 
pleasure to the opportunity of making the acquaintance 
of you and Mrs. Helmholtz, and joins me in hoping that 
you will be our guests during the meeting of the 

We are now on our way to Philadelphia, where I am 
to be one of the judges for scientific apparatus during 
June. We intend to be in Glasgow by the end of July, 
but " Continental Hotel, Philadelphia," would find me for 
a letter posted before the end of June. 

We have had a very fine passage across, with just 
enough of rough weather to test thoroughly a new com 
pass, which I shall show you when you come to Glasgow. 
It behaved perfectly well throughout, notwithstanding a 
great shaking from the screw (which almost prevents me 
from being able to write legibly). 

I have also been trying soundings by pianoforte wire 
from the steamer going at 14 knots, and succeeded in 
getting the bottom with ease in 40 fathoms. But I dare 
say you will hear enough and more than enough of such 
matters when you come to Glasgow so I need not trouble 
you with them now. Believe me, yours very truly, 


The members of the group of judges met on 
May 25 and elected Sir William as president, Pro 
fessor Joseph Henry consenting to preside until 
his arrival. He reached Philadelphia on June 5, 
and stayed till June 28. He specially undertook 
to write reports on electrical and magnetic apparatus 
and telegraphy. The general report on instru 
ments was written by Henry. Of the 385 reports 


of specific awards in these classes, no fewer than 
forty-one were written by Thomson, the most 
important being as follows : 

I. Edison s Automatic Telegraph ; 3. Graham Bell s 
Telephone and Multiple Telegraph ; 4. Elisha Gray s 
Electric Telephone and Multiple Telegraph ; 5. Philps s 
Printing Telegraph; 6. Quadruplex Telegraph; 14. 
Gray s Printing Telegraph ; 1 9. Farmer s Magneto-electric 
Machine; 24. Gramme s Magneto-electric Machine; 27. 
Siemens s Submarine Cables; 221. Lyman s Deep Sea 
Wave Machine; 230. Ritchie s Floating Compass ; 247. 
Wallace s Regulator for Electric Light; 359. Jamin s 
Powerful Steel Magnet ; 383. Edison s Electric Pen. 

The Report No. 3, on Bell s Electrical Inven 
tions, comprises : ist, a description of his Multiple 
Telegraph, and 2nd, of his Electric Telephone. 
The latter is as follows : 

In addition to his electro - phonetic multiple tele 
graph, Mr. Graham Bell exhibits apparatus by which he 
has achieved a result of transcendent scientific interest 
the transmission of spoken words by electric currents 
through a telegraph wire. To obtain this result, or 
even to make a first step towards it the transmission of 
different qualities of sound, such as the vowel sounds 
Mr. Bell perceived that he must produce a variation of 
strength of current in the telegraph wire as nearly as 
may be in exact proportion to the velocity of a particle 
of air moved by the sound ; and he invented a method 
of doing so a piece of iron attached to a membrane, and 
thus moved to and fro in the neighbourhood of an 
electro-magnet, which has proved perfectly successful. 
The battery and wire of this electro-magnet are in circuit 
with the telegraph wire and the wire of another electro 
magnet at the receiving station. This second electro 
magnet has a solid bar of iron for core, which is 


connected at one end, by a thick disc of iron, to an iron 
tube surrounding the coil and bar. The free circular end 
of the tube constitutes one pole of the electro-magnet, 
and the adjacent free end of the bar-core the other. A 
thin circular iron disc held pressed against the end of the 
tube l by the electro-magnetic attraction, and free to 
vibrate through a very small space without touching the 
central pole, constitutes the sounder by which the electric 
effect is reconverted into sound. With my ear pressed 
against this disc, I heard it speak distinctly several 
sentences, first of simple monosyllables, " To be or not to 
be " (marvellously distinct) ; afterwards sentences from a 
newspaper, " S.S. Cox has arrived." (I failed to hear the 
" S.S. Cox," but the " has arrived " I heard with perfect 
distinctness); then "City of New York," "Senator 
Morton," " The Senate has passed a resolution to print 
I ooo extra copies," " The Americans in London have 
made arrangements to celebrate the Fourth of July." I 
need scarcely say I was astonished and delighted ; so 
were others, including some other judges of our group, 
who witnessed the experiments and verified with their 
own ears the electric transmission of speech. This, 
perhaps the greatest marvel hitherto achieved by the 
electric telegraph, has been obtained by appliances of 
quite a homespun and rudimentary character. With 
somewhat more advanced plans and more powerful 
apparatus, we may confidently expect that Mr. Bell will 
give us the means of making voice and spoken words 
audible through the electric wire to an ear hundreds of 
miles distant. 

1 It will be remembered that Sir William Thomson brought a pair of 
instruments back from America, showed them at the British Association at 
Glasgow, made private trials of them before and after the meeting, but got no 
good results, and appears to have been misled by the attachment of the iron 
diaphragm of the receiver (which was in this instrument screwed down) into 
supposing that in some way it acted differently from those shown at Phil 
adelphia. In the subsequent litigation in this country it was successfully 
maintained that Thomson s discourse and his exhibition of the American 
instruments did not constitute an anticipation in this country of the telephone 
as patented here for Bell by Morgan Browne, as altered by amendment and 


Report No. 24 on Gramme s machines gives a 
curious rudimentary theory of the dynamo, which it 
recommends as a subject for scientific inquiry. 

Returning to England he wrote, on Aug. 2, a 
long letter to his former student, Professor John 
Perry, then in Japan, who had sent him the results 
of a research, by Professor Ayrton and himself, on 
Contact Electricity : 

I wish I had more time to keep up a correspondence 
with you and Ayrton, and other good friends of our 
laboratory corps, now in many parts of the world. Please 
tell Ayrton and Dyer this from me. You might also tell 
them that I have just returned from America, where I 
passed a month in most interesting work at Philadelphia 
where I was judge. . . . Lady Thomson was with me, 
and we had a very interesting trip in America, in the 
course of which we saw Niagara Falls, Toronto, Mon 
treal, Boston, and Newport. ... I made soundings 
from the Russia and Scythia going at 14 knots without 
reducing speed. I found it perfectly easy to haul in the 
wire, of which I sometimes had as much as 300 fathoms 
with a 22 Ib. iron sinker and a pressure-gauge for 
measuring the depth. I found bottom in 68 fathoms 
quite unexpectedly in a place where 1900 fathoms was 
marked on the chart. ... I have been so pulled about 
from the beginning of last winter up to the present time 
by pressing engagements that I have never yet succeeded 
in completing for publication our joint paper on the 
Capillary Surface of Revolution. I hope, however, soon to 
be able to overtake the work of preparing it for press. 

He wrote again to Helmholtz : 

Aug. 9, 1876. 

DEAR HELMHOLTZ I wrote to you from New York, 
on my arrival there at the end of May, to say that it 
would give myself and my wife much pleasure if you and 


Mrs. Helmholtz will stay with us in the University during 
the meeting of the British Association to commence on 
the 4th of September in Glasgow. 

I hope you received my letter and have a favourable 
answer to give, or have already sent one which may be 
wandering about in America (where we were rather 
unfortunate in missing letters). Will you let me have a 
line to say if we may expect you. You will find our 
house and ourselves in Glasgow ready to welcome you 
on the 4th ; but in any case don t be later than the 
afternoon of the 5th, as Dr. Andrews opening address 
will be on the evening of that day. 

Hoping to see you soon I say no more just now 
(except that I am at work every moment that the Lalla 
Rookh permits on precession and nutation of a rotating 
liquid in a rigid ellipsoidal shell). We shall have a great 
deal to talk over when you come. Yours always truly, 


P.S. I find that the quasi -rigidity produced by 
vortex motion is such that a rotating liquid enclosed in a 
rigid shell giving a boundary to the liquid of any non- 
spherical figure of revolution, moves approximately as if 
it were a rigid body, when the shell is turned slowly 
round any axis, or when any periodic motion having 
a great multiple of the period of the fluid s rotation, is 
given to the shell. I have verified or illustrated this by 
a large globe of thin sheet copper, made slightly oblate 
and filled with water. It is provided with a point to 
spin on, and a stem to spin it, and it spins very much 
like a solid top, but more steadily ! Quick nutations 
become rapidly extinguished, and even the slower pre 
cession wears away sooner than it does in a solid top. 
So that the liquid top very soon comes to " sleep " 
spinning round a vertical axis. 

At the British Association of 1876, held at 
Glasgow in the University buildings, Sir William 
was in great force. He presided over the Physical 


and Mathematical Section, giving an address, the 
first part of which was devoted to what he had 
seen in America, the progress of science in her 
universities and in her navy, the wonders of the 
exhibition, the telephone " the greatest by far of 
all the marvels of the electric telegraph" the 
administration of patent law. Then he turned to 
his real subject : 

A conversation which I had with Professor Newcomb 
one evening last June in Professor Henry s drawing-room 
in the Smithsonian Institution, Washington, has forced me 
to give all my spare thoughts ever since to Hopkins s 
problem of Precession and Nutation, assuming the earth 
a rigid spheroidal shell filled with liquid. Six weeks ago, 
when I landed in England, after a most interesting trip 
to America and back, and became painfully conscious that 
I must have the honour to address you here to-day, I 
wished to write an address, of which science in America 
should be the subject . . . But the stimulus of intercourse 
with American scientific men left no place in my mind 
for framing or attempting to frame a report on American 
science. Disturbed by Newcomb s suspicions of the earth s 
irregularities as a time-keeper, I could think of nothing 
but precession and nutation, and tides and monsoons, and 
settlements of the equatoreal regions, and melting of polar 
ice. Week after week passed before I could put down 
two words which I could read to you here to-day ; and so 
I have nothing to offer for my address but a review of 
evidence regarding the physical conditions of the earth ; 
its internal temperature ; the fluidity or solidity of its 
interior substance ; the rigidity, elasticity, plasticity of its 
external figure ; and the permanence or variability of its 
period and axis of rotation. 

After this preamble came the discourse (reprinted 
in vol. ii. of the Popular Lectures, p. 238) on the 



Physical Condition of the Earth. Amongst other 
things it contained the conclusion, that examination 
of underground temperatures showed the age of 
the earth to be between 90 millions and 50 millions 
of years. Further, we might be quite sure that the 
earth is solid in its interior, any internal spaces 
occupied by lava or other liquid being small in 
comparison with the whole. The hypothesis of a 
rigid crust enclosing liquid violates dynamical 
astronomy as well as physics ; and the tides decide 
against a flexible crust covering a liquid interior. 
But now thrice to slay the slain : suppose the earth 
to be a thin crust of rock resting on liquid matter, 
its equilibrium would be unstable ! The axis of 
the earth, may in the slow subsidences of ocean- 
beds and the gradual upheaval of continents, 
gradually have shifted, and the poles may have 
changed their positions by as much as 10, 20, 30, 
or 40 degrees, without at any time causing any 
perceptible sudden disturbance of land or water. 
Lastly, since the date on which an eclipse of the 
moon was seen in Babylon in 721 B.C., the earth 
has slowed down in her rotation by r i^ seconds 
per annum ; while apparently, in consequence of 
some settlement in the equatoreal regions, the earth, 
which in the twelve years from 1850 to 1862 lost 
some 7 seconds, began going faster again, and 
gained 8 seconds from 1862 to 1872. 

To the ordinary business of the section Sir 
William Thomson contributed no fewer than twelve 
papers. These were : on Precessional Motion of 


a Liquid ; on Secular Diffusion of Liquids ; on a 
Case of Instability of Steady Motion ; on the 
Nutation of a Solid Shell containing Liquid ; on 
Compass Correction ; Effects of Stress on Magne 
tization ; on Contact Electricity ; on a New Form 
of Astronomical Clock ; on Deep-sea Soundings 
in a Ship moving at High Speed ; on Naval Sig 
nalling ; on a Practical Method of Tuning a 
Major Third ; and a Physical Explanation of the 
Mackerel Sky. The last two have never been 
published ; but the substance of the earlier of the 
two was given in 1878 in another paper, 1 and shows 
two points of interest. The " revolving " character 
of the sound heard in the slow beats of an imperfect 
unison proves that, in a sense, the ear can perceive 
phase as well as pitch in a simple tone. Secondly, 
when tuning a major third by the beats heard if 
the tuning is imperfect, the beats become much 
more marked if at the same time a perfectly tuned 
fifth is introduced. The explanation given of the 
mackerel sky 2 was that there are two strata of 
cloud one moving over the other, the slipping of 
one stratum over the other producing waves, in 
which portions of the air rose and fell. Difference 
of temperature was not necessary ; but the essential 
was that one or other of the two strata should be 
very near the point of hygrometric saturation ; for 
then it would be clear when it sank to its lowest 
point and cloudy when it rose to its highest. The 

1 " On Beats of Imperfect Harmonies," Proc. Roy. Soc. Edin. ix. p. 602, 
April 1878 ; reprinted in Pop. Lectures, ii. p. 394. 

a See Symonis Monthly Meteorological Magazine, xi. p. 131, 1876. 



new Astronomical Clock, which was mentioned 
amongst the communications to the section, had 
been described in 1869 to the Royal Society, and 
was now on view in the hall of Sir William s house 
at the University. It had a modified dead-beat 
escapement, in which the pallets were touched for 
but one three-hundredth part of the beat by the 
escapement tooth, and so arranged that the action 
of the escapement did not stop the train of 

Nature, of Sept. 7, 1876, contained a delightful 
biography of Sir William Thomson, compiled by 
Professor Tait, and illustrated by Jeens s exquisite 
portrait engraved on steel. It concluded as follows: 

The following opinion of Sir William Thomson s merit 
as a worker in science has been sent us by Prof. Helm- 
holtz : " His peculiar merit, according to my own opinion, 
consists in his method of treating problems of mathe 
matical physics. He has striven with great consistency 
to purify the mathematical theory from hypothetical 
assumptions which were not a pure expression of the 
facts. In this way he has done very much to destroy 
the old unnatural separation between experimental and 
mathematical physics, and to reduce the latter to a precise 
and pure expression of the laws of phenomena. He is 
an eminent mathematician, but the gift to translate real 
facts into mathematical equations, and vice versa, is by far 
more rare than that to find the solution of a given mathe 
matical problem, and in this direction Sir William Thomson 
is most eminent and original. His electrical instruments 
and methods of observation, by which he has rendered 
amongst other things electrostatical phenomena as pre 
cisely measurable as magnetic or galvanic forces, give the 
most striking illustration how much can be gained for 
practical purposes by a clear insight into theoretical 


questions ; and the series of his papers on thermodynamics 
and the experimental confirmations of several most sur 
prising theoretical conclusions, deduced from Carnot s 
axiom, point in the same direction." 

British science may be congratulated on the fact that 
in Sir William Thomson the most brilliant genius of the 
investigator is associated with the most lovable qualities 
of the man. His single-minded enthusiasm for the pro 
motion of knowledge, his wealth of kindliness for younger 
men and fellow-workers, and his splendid modesty, are 
among the qualities for which those who know him best 
admire him most. 

Sep. 1 8, 1876. 

MY DEAR HELMHOLTZ We were very sorry not to 
have you with us at the British Association, and to hear 
that your not feeling well enough to come would deprive 
us of this pleasure. I hope you are now quite re 
established in health, and have fully enjoyed your sojourn 
among the mountains. 

If you come so far as London to see the exhibition of 
Physical Apparatus in Kensington, will you not come a 
little farther and see us in the University or the Lalla 

We shall probably remain living chiefly on board the 
yacht till about the middle of October, soon after which 
we go to London and Cambridge, where I have to attend 
my annual College meeting at Peterhouse on the 3ist of 
October. . . . Believe me, yours always truly, 


In October 1876 Sir William Thomson s friend 
and quondam College Tutor, the Rev. H. W. 
Cookson, died, and with his death the Mastership 
of Peterhouse became vacant. Some of the Fellows 
desired to have Sir William Thomson as Master, 
while others were in favour of the Rev. James 



Porter, his junior by three years, who for some 
time had been Tutor, and was still holding the 
office. At the election, which took place on 
October 28, 1876, in the College Chapel according 
to Statute, Porter received a majority of votes, and 
became Master. On Porter s death in 1900, Lord 
Kelvin was again approached with a view to his 
accepting the Mastership, but he definitely declined ; 
and, on the candidature of Dr. A. W. Ward being 
brought to his notice, he united with his Fellows in 
electing him to that office. 

In February 1877 Sir William lectured at Govan 
on Telegraph and Lighthouse Signals, advocating 
the teaching of the Morse alphabet in all schools, and 
denouncing the " Tite Barnacles " of the Admiralty 
and other Boards for opposing his plan of giving 
each lighthouse a distinctive kind of flashing light, 
as if sailors could not learn to distinguish long and 
short flashes ! 

On Feb. 18, 1877, he wrote to Mrs. King: 

The compass causes a quite unprecedented addition 
to my occupations, but it is very interesting, and as it 
takes me a good deal about shipping it is not like plodding 
at writing or " book work." Willy Bottomley is most 
helpful, and has got on very well with some adjustments 
which he has done all himself. He was down with me 
from Friday morning till Saturday evening in a new ship, 
Balmoral Castle, belonging to Messrs. Donald Currie & Co., 
which has been fitted out with three of my compasses. 
We went to Gareloch head on Friday evening and "swung" 
early next morning to adjust compasses. / should not 
have required this, but there were two other compasses 
on board, and it was thought right to have the ordinary 


certificate of the usual adjustment, both for mine and 

He wrote to Lord Rayleigh : 

March 8, 1877. 

DEAR LORD RAYLEIGH I see by this morning s 
paper that you and Lady Rayleigh are to be passengers 
in the Balmoral Castle to-morrow from Dartmouth for 
the Cape. There are three of my compasses on board 
an azimuth compass, and two steering compasses in the 
wheel house. 

I should be very glad if you would look at them a 
little and see how they behave, and much obliged if you 
would write me a line from Madeira or the Cape, telling 
me about them. 

The enclosed printed papers about the compass (and 
a new sounding machine which has made a good beginning 
already in several ships) will tell you all you may care 
to know about my system of adjustment. 

My wife joins in wishing you and Lady Rayleigh a 
pleasant passage, and I remain, yours very truly, 


On Feb. 22 he gave to the Glasgow Geological 
Society a lecture on Geological Climate, which has 
been dealt with in Chapter XIII. p. 536; and on 
April 24 he lectured to the Institution of Engineers 
and Shipbuilders in Scotland on Compass-adjustment 
in the Clyde. The compass work, described in 
detail in the next chapter, was assuming a commer 
cial importance. The greater part of his time was 
spent in White s workshops, whither he would repair 
almost daily after he had finished his morning lecture 
and had made the round of the laboratory. The 
correspondence in which he was involved was very 


heavy for several years. He was also busy with 
Tait revising the Treatise on Natural Philosophy, 
a second edition of which was now called for. On 
March 7 appeared in the Scotsman his letter on 
vivisection, dealt with subsequently (p. 1105). In 
April he wrote to Hopkinson on the inductive 
capacity of glass, with which the latter had experi 
mented. He encouraged him to try as many dif 
ferent kinds of glass as possible, and find out 
whether glass of the same composition always had 
the same electrostatic capacity. 

On May 15 he wrote again to Hopkinson that 
he had just received splendid reports as to the 
Holy wood Bank Lighthouse at Belfast, for which 
he had designed a distinctive eclipsing light. He 
showed these reports to the Elder Brethren of 
Trinity House, to whom he had that day gone to 
explain his compass and his sounding machine. 
He was to sail for Madeira in a few days in the 
Lalla Rookh from Cowes. 

To Mrs. King he wrote on July i from Madeira, 
giving a narrative of the voyage : 

... I have been busy ever since we got away from 
London, at Dartmouth, Plymouth, Vigo, and at sea and 
here, with Tides Report for the British Association, etc., 
etc., and the great book (T and T ), it chiefly. I hoped 
to have a large instalment for the printers off by this 
mail, but the steamer has been announced suddenly to 
night and goes away early in the morning, so this must 
wait a little longer. On the voyage, and since coming 
here, I have also had much to do in trials of the sounding 
machine leading to what I hope is to be considerable 



The return voyage, from August 5 to August 7, 
in thick weather, afforded a triumphant proof of the 
advantage of taking flying soundings. Sir William 
saw to the fitting up, on board H.M.S. Minotaur, 
of his own compass and sounding machine before 
he went on to Plymouth for the British Association 
on August 15. 

At Plymouth Sir William was ubiquitous. He 
read the report on the tides of Mauritius drawn up 
by himself and Captain Evans. He spoke on the 
magnetic susceptibility of iron ; on Laplace s tidal 
equation ; on the variations of barometric pressure ; 
on the marine azimuth mirror ; on his machine for 
taking flying soundings ; on his depth-recorder ; on 
his compass ; on the Needles lighthouse, for which 
he advocated a distinctive flashing light. He added 
to the gaiety of the mathematical section by raising 
the question (see p. 610) whether a beetle could not 
live on a meteoric voyage from Mars to the earth. 
He and Dr. Samuel Haughton then delighted the 
audience by talking in their respective brogues into 
Graham Bell s telephone, which Mr. (now Sir 
William) Preece had brought over. 

On October 26 Sir William urged on the Ship 
masters Society the need for lighthouse reform. 
He wrote on the same subject to The Times on 
November 12. 

In 1877 he was elected a foreign associate of the 
Institut of France in place of von Baer. 

In the previous year the Italian Society of 
Science, known as the De Quaranta, had awarded 



him the Matteucci prize as " the one who has 
contributed the most in the world to the advance 
ment of science by his writings and discoveries." 

Down to this date electric lighting, in the modern 
sense, was practically unknown. Solitary arc lamps 
had been used for theatre-effects, for magic-lantern 
work, and, in rare cases, for lighthouses. Primitive 
dynamo-electric machines, based on Faraday s great 
discovery of 1831, had been built. Thomson had 
even reported on Holmes s machine, which was a 
feature of the 1862 Exhibition. He had never 
concerned himself, however, either with electric 
lamps or with electric generators. Even the 
advances made in 1866-67 by Wilde, Varley, 
Siemens, and Wheatstone had left him uncon 
cerned. Gramme s commercial machines of 1871 
had apparently not interested him till he reported 
on them for the Philadelphia Exhibition of 1876. 
Down to January i, 1880, he had read no fewer 
than 360 scientific papers, and taken out 17 patents ; 
but not one of these touched even the fringe of the 
question of electrical engineering, the generation of 
electric energy for lighting and power. Once only, 
in 1857 (see p. 397), had he ever spoken on the 
possibility of using electric motive power, and on 
that occasion he put it aside as impracticable. But 
the question was raised in a discussion at the Insti 
tution of Civil Engineers on January 22, 1878, on 
Siemens s recent improvements described in a paper 
by Messrs. Higgs and Brittle; and following up a 
remark of Dr. C. W. Siemens on the possibility of 


distant transmission, Sir William Thomson spoke. 
With characteristic agility of mind he leapt forward 
to the logical issue : 

He believed that with an exceedingly moderate amount 
of copper it would be possible to carry the electric energy 
for one hundred, or two hundred, or one thousand electric 
lights to a distance of several hundred miles. The 
economical and engineering moral of the theory appeared 
to be that towns henceforth would be lighted by coal 
burned at the pit s mouth, where it was cheapest. The 
carnage expense of electricity was nothing, while that of 
coal was sometimes the greater part of its cost. The 
dross at the pit s mouth (which formerly was wasted) 
could be used for working dynamo-engines of the most 
economical kind, and in that way he had no doubt that 
the illumination of great towns would be reduced to a 
small fraction of the present expense. Nothing could 
exceed the practical importance of the fact to which 
attention had been called : that no addition was required 
to the quantity of copper to develop the electric light at 
a distance. The same remarks would apply to the trans 
mission of power. Dr. Siemens had mentioned to him in 
conversation that the power of the Falls of Niagara might 
be transmitted electrically to a distance. The idea seemed 
as fantastic as that of the telephone or the phonograph 
might have seemed thirteen months ago ; but what was 
chimerical then was an accomplished fact now. He 
thought it might be expected that, before long, towns 
would be illuminated at night by an electric light pro 
duced at the pit s mouth or by a distant waterfall. The 
power transmissible by the machines was not simply 
sufficient for sewing-machines and turning-lathes, but, by 
putting together a sufficient number, any amount of horse 
power might be developed. Taking the case of the 
machines required to develop one thousand H.P., he 
believed it would be found comparable with the cost of a 
one thousand H.P. engine ; and he need not point out the 
vast economy to be obtained by the use of such a fall as 


that of Niagara, or the employment of waste coal at the 
pit s mouth. . . . 

For lighthouses, the great adaptability of the electric 
light to furnish increase of power when wanted gave it a 
value which no other source of light possessed. . . . 

The value of electric light was also of great importance 
in regard to public health. The detrimental character of 
the fumes of gas in public buildings was well known. 
There were no fumes from the electric light, and the 
quantity of heat generated by it was vastly less than that 
produced by gas or oil for the production of the same 
light. It had been stated by a previous speaker that the 
gas employed in an economical gas engine to drive a 
machine to produce the electric light would produce the 
same light with one-fifteenth part of the combustion ; and 
that meant not only increased economy, but a great 
advantage in regard to public health. 

When a year later Sir William gave evidence 
before the Select Committee of the House of 
Commons on Electric Light (see p. 691), he re 
peated much of the above, adding that the manufac 
tories of whole towns might be driven by a supply of 
electric power so transmitted. To such application 
of electricity as motive power there was no limit ; 
it might do all the work that could now be done 
by the most powerful steam-engine. He advocated 
that by legislation in the interests of the nation, 
and of mankind, they should remove all obstacles, 
such as those arising from vested interests, and 
should encourage inventors to the utmost. There 
would be no danger of terrible effects from the 
employment of electric power, because the currents 
employed would be continuous and not alternating ! 


Commenting on this evidence, Nature remarked : 
" This may be called a fanatical view of the electric 
light " ! 

About this time Sir William Thomson undertook 
to write an article on " Elasticity " for the Encyclo 
pedia Britannica (ninth edition). Much of the 
theoretical matter had already been worked out by 
him and his brother James in his Royal Society 
memoir (p. 319, above), or was already embodied 
in the Treatise of Thomson and Tait, but the com 
pilation of descriptive matter and the collection of 
numerical data involved much labour ; and new 
experiments had to be made in the laboratory by 
Donald Macfarlane, and by Andrew Gray and 
Thomas Gray, to fill up the lacunae. To the article 
was appended a reprint of the " Mathematical 
Theory of Elasticity," in seventeen short chapters, 
dealing with strains and stresses in homogeneous 
bodies, both those that are isotropic (that is, 
destitute of "grain" and alike in every direction) 
and those that are aeolotropic (having definite 
structure, different in different directions, as in 
wood or in crystals). Following Green, he showed 
that, in the general case, completely to define the 
elasticity of a body there were required twenty- 
one coefficients, six of which were the principal 
elasticities, and fifteen others depending on the 
type of strain. He classified strains, and defined the 
various moduluses that specify the relation between 
the strains and the stresses that produce them. 

The importance of Lord Kelvin s many con- 


tributions to the subject may be gathered from the 
fact that in Professor Karl Pearson s standard work, 
the History of Elasticity, more than one hundred 
pages are devoted to them. The late Professor G. F. 
FitzGerald has given the following appreciation: 

His treatment of the elasticity of solids has largely 
influenced the whole British school of elasticians, and his 
fecundity in devising elastic mechanisms has emphasized 
his fight against the supposed necessity that, in a simple 
solid, the rigidity is three-fifths of the compressibility. 
This may, no doubt, be used as a definition of a simple 
solid, but in that case hardly any value can be attached to a 
relation that is hardly ever of any service. Our knowledge 
of the structure of matter is far too meagre for us to 
deduce, a priori, such a result, and Lord Kelvin has always 
advocated the scientific method of proving by induction 
that, in a large number of cases, we can reduce the elastic 
properties of a solid to its rigidity and compressibility, and 
deduce its behaviour under stress from a knowledge of 
these two qualities. 

A proof of the " Elasticity " article being sent to 
Tait, it was returned with the following effusion 
written on the last page. The last two verses are 
by Tait, the rest by Maxwell : 

Count up the stresses O ; 
Weigh well the stresses O. 
For what s our life but just a strife 
Where strains elicit stresses O ? 

To Nature blind my torpid mind 
Cared not what cork or jelly meant, 

Nor could expound the stresses round 
The differential element. 

Now, better taught, maturer thought 

That state of mind reverses O, 
And finds great fun in twenty-one 

Elastic moduluses O. 


He s blest who dares let worldly cares 

And worldly people joy on all, 
And learns to express six types of stress, 

Each unto each orthogonal. 

Vex not my ears, ye crystal spheres, 

Your harmony s insipid O : 
But play again that six-fold strain 

My parallelepiped O ! 

Joy to the fair, be gems their care, 

Ornated trains and tresses O ; 
But leave the sage his bliss, his rage, 

Related strains and stresses O ! 

Green grew the stresses O ; 
T. slew the stresses O. 
The hardest grind I e er did find 
Was reading T. on stresses O. 

For the Encyclopedia also he afterwards wrote 
the article on " Heat." It begins with the sentence, 
" Heat is a property of matter which first became 
known to us by one of six different senses." He 
distinguished between the sense of temperature and 
the tactile (or muscular) sense by which we perceive 
the roughness or smoothness of things. The article 
consisted of four principal sections : calorimetry, 
thermometry, transference of heat, and statistical 
tables. The calorimetric section is distinguished 
by the special prominence given to Joule s work, 
and by a comment on the circumstance that fifty 
years passed before the scientific world was con 
verted by the experiments of Davy and Rumford 
to the rational conclusion as to the non-materiality 
of heat : " a remarkable instance of the tremendous 
efficiency of bad logic in confounding public opinion 
and obstructing true philosophic thought." The 


section on thermometry is marked by extreme 
precision of language, and the emphasis laid on 
Regnault s work with " mercury- in -glass " and 
" air-in-glass " thermometers. A large amount of 
space is devoted to " water-steam-pressure-ther 
mometers " and sulphurous acid thermometers, by 
means of which he was endeavouring to realize 
actual thermodynamic instruments. He recom 
mended for practical use constant - pressure gas 
thermometers of nitrogen or hydrogen. Under 
transference of heat he referred to Fourier s Thtorie 
Analytique and its solutions of heat problems, " of 
which it is difficult to say whether their uniquely 
original quality, or their transcendent interest, or 
their perennially important instructiveness for 
physical science, is most to be praised." At 
various points in the article the work done by 
himself and his assistants in the Glasgow laboratory, 
in the determination of constants of conductivity 
and of emissivity, is emphasized. He added a 
strange appendix : a compendium * of " Fourier 
mathematics," admirable in itself, but thrown to 
gether like mere hints to a lecturer. 

Returning to May 1878, we find Thomson busy 
with A. M. Mayer s groups of floating magnets, of 
which he wrote to Nature, and with a Harmonic 
Analyser based on the mechanical integrator devised 
by his brother James (p. 692). On May 10 he dis 
coursed at the Royal Institution on the Effects 

1 Originally written in 1850 in his mathematical diary, and published in 
the Quarterly Journal of Mathematics in 1856 ; finally reprinted in Math, and 
Phys. Papers, ii. p. 41, in 1884. 


of Stress on Magnetization. On May 20 he 
was addressing the Edinburgh Royal Society on 
Columnar Vortices. In the same month he gave 
two papers to the Physical Society of London. 
At the Paris Exhibition of 1878 he was awarded 
a gold medal for his compass and sounding machine. 
To the British Association at Dublin he sent three 
papers : on the Tides of the Mediterranean (along 
with Captain Sir F. J. Evans) ; on the Magnetism 
of Ships ; and on the Influence of the Straits of 
Dover on the Channel Tides. 

In November 1878 we find him again urging in 
The Times the question of distinguishing lights for 
lighthouses. In January 1879 there appeared in 
The Times an anonymous article on Aids to Safe 
Navigation, from which it may be gathered that 
the sounding machine had been tried on H.M.S. 
Minotaur to the satisfaction of Admirals Beauchamp 
Seymour and Lord Walter Kerr. The latest im 
provements in the compass, the azimuth mirror, and 
the deflector were mentioned and praised. 

Having, in February 1879, to lecture at the 
Royal Institution on the "sorting demon " (p. 286), 
of Maxwell, he stayed with his friend Sir William 
Siemens, busy over the evidence which each of 
them was shortly to give before the Select Com 
mittee on Electric Light. Sir William and Lady 
Thomson spent a week in June at the Siemenses 
country house near Tunbridge Wells. 

In his evidence before the Committee, Sir 
William referred to the problem of utilizing the 


Falls of Niagara, and to Siemens s proposals as 
outlined in his presidential address to the Iron and 
Steel Institute in 1877. He gave an estimate of 
the quantity of copper suitable for the economical 
transmission of power by electricity to any distance, 
and applied the calculation to the case of Niagara. 
He pointed out that, under practically realizable 
conditions of intensity, a copper wire half an inch in 
diameter would suffice to take 26,250 horse-power 
from water-wheels driven by the Fall, and (losing 
only 20 per cent on the way) to yield 21,000 horse 
power at a distance of 300 British statute miles ; 
the prime cost of the copper amounting to ,60,000, 
or less than 3 per horse-power actually yielded at 
the distant station. 

All through the preceding months Sir William 
had been busy revising " Thomson and Tait," and 
the first part of Vol. I. of the new edition appeared 
in June. It was reviewed in Nature of July 3, 
1879, by Clerk Maxwell almost the last thing 
done before his lamented death. Maxwell quoted 
from p. 225 the statement (obviously adopted from 
Newton) that " matter has an innate power of 
resisting external influences, so that every body, as 
far as it can, remains at rest or moves uniformly in 
a straight line." " Is it a fact," asked Maxwell, to 
whom " this Manichaean doctrine of the innate 
depravity of matter " seemed superfluous, " that 
1 matter has any power, either innate or acquired, 
of resisting external influences ? Is a cup of tea to 
be accused of having an innate power of resisting 


the sweetening influence of sugar because it per 
sistently refuses to turn sweet unless the sugar is 
actually put into it ? " Maxwell praised, as a 
feature of the new edition, the greater use of the 
generalized equations of motion, which had too 
long been left neglected " in sanctuary of profound 
mathematics " : 

The credit of breaking up the monopoly of the great 
masters of the spell, and making all their charms familiar 
in our ears as household words, belongs in great measure 
to Thomson and Tait. The two northern wizards were 
the first who, without compunction or dread, uttered in 
their mother tongue the true and proper names of those 
intellectual ancepts which the magicians of old were wont 
to invoke only by the aid of muttered symbols and inar 
ticulate equations. And now the feeblest among us can 
repeat the words of power and take part in dynamical 
discussions which but a few years ago we should have left 
for our betters. 

This would seem the appropriate place for a 
brief mention of the very remarkable series of 
machines for the performance of mathematical opera 
tions which Sir William Thomson designed between 
the years 1876 and 1879. His brother, Professor 
James Thomson, had conceived a mechanism 1 
called the disk-ball-cylinder integrator which en 
abled any desired fraction of the motion of a re 
volving disc to be communicated to a cylinder 
pivoted above it, by the intermediation of a heavy 
metal ball or globe which rested on the disk and 
pressed against the cylinder. If the globe lay 

1 "An Integrating Machine, being a New Kinematic Principle," Proc. 
Roy. Soc. xxiv. p. 262, 1876. 


actually on the centre of the disk it communicated 
no motion to the cylinder. If it were shifted (by 
a suitable fork) along a diameter of the disk, parallel 
to the cylinder, to a point near the outer edge of 
the revolving disk, it caused the cylinder to revolve 
actively. In intermediate positions the amount of 
motion so communicated was proportional to its 
distance from the centre. On learning of this in 
genious combination, Sir William immediately per 
ceived that it could be applied not only to such 
simple integrations as the quadrature of curves, but 
to other much more difficult problems of the calculus, 
the integration of products, the solution of linear 
differential equations, and above all to the mechanical 
performance of harmonic analysis, the process by 
which, when any complicated (single-valued) periodic 
function is given, it can be resolved into a series 
of constituent terms which themselves are simply 
periodic. The heavy arithmetical labour involved 
in the ordinary calculation of the integrals might 
thus be saved. Lord Kelvin s own account will be 
found in the Appendix on Continuous Calculating 
Machines at the end of Vol. I. Part I. of the 
Thomson and Tait Treatise. The principal publi 
cations on the subject were : 

1. On an instrument for calculating the integral of the 
product of two given functions. Proc. Roy. Soc. xxiv. p. 266, 

2. Mechanical integration of the linear differential equations 
of the second order, with variable co-efficients. Ib. xxiv. p. 269. 

3. Mechanical integration of the general linear differential 
equation of any order with variable co-efficients. Ib. xxiv. p. 271. 

4. An application of James Thomson s integrator to harmonic 


analysis of meteorological, tidal, and other phenomena, and to 
the integration of differential equations. Jt. Soc. Edin. Proc. 
ix. p. 138, 1876. 

5. Harmonic Analyser. Proc. Roy. Soc. xxvii. p. 371, 1878. 

6. On a machine for the solution of simultaneous linear 
equations. Ib. xxviii. p. in, 1879. 

7. The tide-gauge, tidal harmonic analyser, and tide pre- 
dicter. Inst. Civil Engineers Proc. Ixv. pp. 2-25, 1881. 

The Harmonic Analyser for calculating the ele 
ments of tides was constructed. An example may 
be seen in the Science Collections at South Ken 
sington. The machine for solving differential equa 
tions did not prove to be practical. 

Clerk Maxwell died on November 5, and thus 
the Cavendish chair at Cambridge became vacant. 
Lord Rayleigh wrote to Sir William Thomson, 
opening the question whether he would exchange 
Glasgow for Cambridge. His reply was decisive : 

LONDON, Nov. 17, 1879. 

DEAR LORD RAYLEIGH Your letter was forwarded 
from Glasgow and reached me here this morning. 

I feel that my destiny is fixed for Glasgow for the 
rest of my life. I felt strongly attracted to Cambridge 
at the time the new chair of Experimental Physics was 
founded, but resolved then to remain in Glasgow. If you 
could see your way to take the chair it would, I am sure, 
be much for the benefit of the University, and of science 
too, as the Cavendish Laboratory would give you means 
of experimenting and zealous and highly instructed assist 
ants and volunteers, and would naturally lead you to 
more of experimental research than might be your lot, 
even with all your zeal and capacity for investigation, if 
you remain independent. If, however, you feel that in 
taking the professorship you would be taking a burden 
on you to any degree uncongenial or inconvenient, or 


tending to occupy time which you might more advan 
tageously spend in writing or in independent research, and 
that you would only hold it till some of the younger men 
might show suitable qualifications, I would not advise you 
to take it. Hopkinson would, I believe, be a candidate 
if you do not accept the chair; and with his strong mathe 
matical foundation, and decided inclination for physical 
science, and particularly for experimental work, I believe 
he would be very successful should he be elected. 

I need not say that it would be a great satisfaction 
and pleasure to myself to look forward to having you at 
Cambridge should you decide to take the professorship. 

Believe me, yours very truly, 




GREAT as were the achievements of Lord Kelvin in 
other directions, his contributions to the science and 
practice of navigation were of no mean importance. 
Fond of the sea from his youth, he had during his 
experiences in the laying of ocean cables, and, later, 
on board his own yacht, become a master in seaman 
ship. " I am a sailor at heart," he declared in 1892, 
in his inaugural address as President of the Institute 
of Marine Engineers. His penchant for sailing is 
shown by the nautical examples given as illustrations 
of hydrodynamical principles in 325 (edition of 
1879) of Thomson and Tait s Natiiral Philosophy, 
where the tendency of a body to turn its flat side 
across the direction of motion through a fluid is 
connected with the steering of a square-rigged ship, 
the " wearing " of a fore-and-aft rigged vessel, and 
the difficulty of getting a ship in a heavy gale out 
of the trough of the sea ; concluding with the re 
mark, that the risk of going ashore in fulfilment 
of Lagranges equations is a frequent incident of 

getting under way" while lifting anchor. 


CH. xvn THE COMPASS 697 

Thomson s contributions to navigation may be 
summarized under seven heads : 

1. His Compass. 

2. His Sounding Machine. 

3. His work on Lighthouse Lights. 

4. His work on Tides, and his Tide Analyser, Tide- 
Gauge, and Tide-Predicting Machines. 

5. His connection with the Admiralty on the Com 
mittee upon the Designs of Ships of War (1871), and on 
the Committee to review the Types of Fighting Ships 

6. His mathematical investigations of Waves in 

7. His tables for facilitating the use of Sumner s 
methods of finding the place of a ship at Sea. 


About the year 1871 Sir William Thomson was 
asked by his friend, the Rev. Norman Macleod, to 
contribute an article to his newly founded magazine 
Good Words. He chose as topic the mariner s 
compass, and was thus caused to direct his attention 
to the construction of that indispensable instrument 
of navigation. He thought he had a pleasant and 
easy task in describing an instrument which had 
been for six hundred years in regular use by 
European mariners ; but when he began he found 
himself compelled to criticize, so grave were the 
defects which he found in the compasses then in 
use. And having noted the defects, his mind, ever 
on the alert as to practical needs, turned toward 
possible improvements ; and so began the work 
that eventually made his name familiar to every 



nautical man. It was not till 1874 that his first 
article was sent to Good Words ; and it was five 
years afterwards when his second article appeared. 
When I tried," he said, "to write on the mariner s 
compass, I found that I did not know nearly enough 
about it. So I had to learn my subject. I have been 
learning it these five years." His Good Words 
articles deal, however, with Terrestrial Magnetism 
in general, and with the early history of the com 
pass, and do not touch his own inventions. 

Many were the defects of the old marine com 
passes in vogue up to 1870. They were often 
sluggish in their action, and apt to stick at times. 
In the Navy they were useless during action, as the 
concussion of the vessel during gun-fire put them 
out of service. During stormy weather, when the 
vessel was rolling, they were liable to oscillate in a 
way that made them misleading. Some of these 
defects arose from the weight of the moving part. 
From time immemorial the compass for use at sea 
has consisted of a pivoted magnet carrying affixed 
above it the circular " card." This card, five 
centuries ago, used to be inscribed with the eight 
principal "winds," divided into halves and quarters, 
so making up the thirty-two "points" that have 
been in use all the world over. Until about 1840 
the magnetic needle was either an oval plate or a 
simple flat bar of steel drilled with a central hole to 
receive the cap by which it was poised on the pin, 
the ends of the bar being pointed. In 1842, as 
the result of the investigations of an Admiralty 

xvii THE COMPASS 699 

committee, the Admiralty Standard Compass was 
adopted. In this the card was seven and a half 
inches in diameter, and under it were fastened four 
" needles" two on each side of the middle each 
needle being a long straight bar of flat clock-spring, 
set with the breadth of the bar perpendicular to the 
card. The card with the needles weighed about 
1600 grains, its weight being borne by a jewelled 
cap fixed in the centre of the card, and resting on a 
fine point of hard iridium alloy. In the merchant 
marine larger compasses, with needles ten, twelve, 
or even fifteen inches long, were favoured. Those 
on board the Great Eastern were eleven and a half 
inches. Sailors like large compass cards, as they 
are more easily read ; and the cards of larger size 
are steadier in a heavy sea. As Thomson himself 
pointed out, the secret of the steadiness of a large 
compass lies in its period of vibration being long. 
On the other hand, it was supposed that the more 
powerful its magnetic moment in proportion to its 
moment of inertia, the better would be the directive 
action of the compass. It may be, from the point 
of view of getting over friction on the pin ; but 
when the ship is rolling in the ocean, the more 
powerful the magnet the less steady will the com 
pass be. The natural period of vibration of the 
Admiralty standard compass is about nineteen 
seconds, that of the ten-inch compass of the mer 
chant ships about twenty-six seconds. The great 
weight of the "card" led to errors due to friction 
on its pivot ; and the sailors used often to kick the 


binnacle to make the card move, or agitated it with a 
twiddling line. Worse than all this, the considerable 
length of the magnets made it difficult to correct the 
errors due to the magnetism of the iron of the ship. 
So long as ships were made of wood, and no iron 
bars or stays were permitted 1 near the compass, it 
would obey fairly the directive action of the earth. 
But when iron ships began to replace the " wooden 
walls," it was found that the magnetism of the ships 
themselves produced serious errors. Early in the 
nineteenth century Flinders had introduced the 
practice of " swinging" the ship, that is, turning 
her slowly round, while the deviations of her com 
pass from the true direction were observed (by 
taking bearings of a distant object) in different 
positions. He also invented the use of the 
" Flinders bar," a rod of soft iron placed near the 
compass to correct for changes in the magnetism 
of the ship due to the vertical component of the 
earth s magnetism. Barlow introduced the plan of 
correcting the influence of the ship s own magnetism 
by placing disks of soft iron in suitable positions 
near the compass. After the mathematical investi 
gations of Poisson and of Airy, about 1838, methods 
of correction by the use of permanent magnets and 
of soft-iron globes were introduced, and Archibald 
Smith had extended the mathematical investigation, 
and had formulated practical rules which were 

1 An instance occurred when the Niagara, a wooden frigate, in laying the 
cable of 1858, was found to have deviated seriously from her course, the 
many tons of iron in the cable on board having produced an unsuspected error 
in her compass. 



adopted by the Admiralty for correcting the devia 
tions of the compass. The magnetism of the hull 
of a ship which thus disturbs the compass, and pre 
vents its pointing truly along the magnetic meridian 
of the place, is partly of a permanent nature, de 
pending on the position in which the ship lies during 
building, and is partly of a temporary nature due to 
the temporary magnetization of the iron of the ship, 
depending on the direction in which she is pointing 
for the moment, whether northwards or southwards, 
or in some oblique position across the magnetic 
meridian. As the magnetism of the ship is thus 
constantly changing, the correction must be an 
automatic one, namely, that effected by masses of 
soft iron subject to the same influences which cause 
the disturbance. To correct for the permanent 
magnetism of the ship, permanent magnets were 
placed in a reversed position beneath the compass- 
bowl in the binnacle ; and to correct for the tempo 
rary induced magnetism of the ship s hull two globes 
of soft iron were placed beside the compass, one on 
either hand, at the level of the compass card, as 
directed by Airy, the then Astronomer- Royal. 
Smaller compasses were also in use, the received 
opinion being that the smaller a card is the more 
correctly it points, but the larger a card the more 
accurately it is read. 

In the course of his investigation Thomson dis 
covered that the long magnets in common use had 
several disadvantages. By being long and power 
ful, they themselves induced magnetism in the 


soft-iron globes used as correctors, and in some cases 
created more error l than before. Only by using much 
larger globes at a greater distance could the long 
needles be corrected. Thus to correct the needles 
of the Great Eastern would have required globes 
weighing more than a hundred tons each ! Aboard 
battleships the effect of gun-fire was disastrous, com 
passes with heavy cards being simply unusable. 

Thomson revolutionized all this. The needles 
must be made short ; yet for accuracy of observa 
tion the card must be kept large ; to diminish 
friction on the pivot it must be made light ; and for 
steadiness its moment of inertia must be increased 
by throwing as much of the weight as possible into 
the rim. He therefore built a gossamer structure 
of threads on a light aluminium rim, below which 
were suspended four, six, or eight slender steel 
needles, and bearing the " card " printed on a circle 
of thin paper with all the central part cut away. 

But all this was not effected without many stages 
of experiment and trial. 

While tentatively proceeding he wrote to the 
acting hydrographer, Captain (later Sir Frederick 
J.) Evans, who had in 1870 published his well- 
known Elementary Manual on the compass. 


DEAR CAPTAIN EVANS As you have kindly excused 
the trouble I have already given you, I am emboldened 
to trouble you farther. 

1 See Archibald Smith and F. J. Evans in Proc. Roy. Soc., April 18, 
1861, p. 179 ; where the errors of the "corrected" standard compass of the 
Great Eastern are given as between 5 and 6. 



What is the whole weight of needle, compass card, and 
magnets, of the best Admiralty compass at present made ? 
Has it two needles, or four, and what are their lengths ? 
I am not sure whether 6 inches is the diameter of the 
card or the length of the longest of the needles. To what 
degree of accuracy can you depend on the readings ? 
What is the greatest displacement at which the compass 
will stick from the correct position when left undisturbed ? 
I presume this is a small fraction of one degree. 

I am disposed to advocate, as better than anything at 
present afloat, a little toy compass on gimbals which I 
have seen lately, made in London, and which is sold for 
1 8s. electro-silvered, or 2 is. electro-gilt. It has one 
needle and a compass card of the usual form, but only 
about an inch diameter. I can read it to a fraction of a 
degree ; and hitherto I have not detected any sticking 
away from the correct position. I have not yet made 
accurate experiments. Its smallness renders it perfectly 
easy to correct perfectly the quadrantal deviation by the 
Liverpool cast-iron cylinders. But I object to the movable 
compass card altogether, and have made a small compass 
with a pair of needles about half an inch long, and a fine 
glass pointer (after the method originally given by Joule 
some twenty-five years ago) which I expect will be 
thoroughly satisfactory. I am arranging it with soft-iron 
correctors for the quadrantal deviation, and an accurately 
graduated magnetic adjustment for the semicircular devia 
tion, by which I shall be able to have the compass kept 
correct from day to day in all latitudes, without losing 
any of the advantage of keeping a complete log of the 
ship s magnetic condition. I hope to be able to bring 
it with me to London and show it to you next week. 
Meantime I would feel much obliged by your answer to my 
questions, if convenient, by return of post ; as besides the 
" biographical sketch " l of Archibald Smith, I have in 

1 In this obituary notice of January 1874 there occurs the following char 
acteristic note : "When the needles of a standard compass are reduced to 
something like half an inch in length, and not till then, will the theoretical 
perfection and beauty, and the great practical merit, of Airy s correction of 


hand a short article on the " Mariner s Compass " for Good 
Words, which should also be finished by the end of this 
wee k. Yours truly, WILLIAM THOMSON. 

Captain Evans, R.N. 

P.S. Can you also tell me the dimensions, number of 
needles, and weight of the largest compass supplied to 
some of these grand modern merchant ships ? From 
yours and Archibald Smith s paper, I understand that 
the standard compass supplied to the Great Eastern 
had a card 1 2 inches diameter ! Is this correct ? Will 
you also tell me, roughly, the period of vibration of a 
standard compass, in London, of your ordinary pattern ? 
I expect that my small compass with glass indicator will 
be altogether free from " hunting " in the roughest weather 
at sea ; and that the amount of heeling-over will be 
directly shown by its performance during the ordinary 
rolling of a ship at sea. 

Evans s reply has not been preserved ; but he 
had not much sympathy with Thomson s ideas. 
In the Glasgow News of March 18, 1874, we find 
a brief description of the first form put forth by 
Thomson : 

Sir William s compass consists of a pair of steel 
needles, on the model of a needle prepared for the 
galvanometer by Dr. Joule, the founder of the science 
of thermodynamics. The needles are each half an inch 
long, and are supported on a framework of aluminium 
and glass rods, weighing in all i^ grains, and hung by a 
single fibre of unspun silk -j^ of an inch long. 

He had two days previously shown the new 
compass to the Royal Society of Edinburgh. 

Writing a week later to Froude, he complains 

the compass by soft-iron and permanent magnets (which theoretically assumes 
the length of the needle to be infinitely small in proportion to its distance from 
the nearest iron or steel) be universally recognised, and have full justice done 
to it in practice." 

xvii THE COMPASS 705 

" how people in all departments of the Admiralty, 
except the construction department, are averse to, 
and how if they could they would be impregnable 
against, all suggestions from without." Evidently 
he had received scant encouragement in that 

Sir William himself, in 1885, on the occasion of 
a lawsuit which arose as to his patents, gave the 
following account of his invention : 

I began to give attention to the mariner s compass 
with a view to its general improvement about 1871, and 
after working at the subject for five years, I took my first 
patent relating to these improvements, namely, my patent 
No. I339,A.D. 1876. In 1874 I communicated a mathe 
matical paper to the British Association, which was pub 
lished in the Philosophical Magazine for that year, in 
which I showed that largeness of vibrational period is 
favourable for steadiness of the compass at sea in stormy 
weather. Up to that time no practical method of obtain 
ing largeness of vibrational period consistently with other 
essential qualities for good working, particularly smallness 
enough of needles to allow the proper correction of the 
compass for the deviations produced by the iron of the 
ship, had been invented. After a year and a half of 
experimental work on land and at sea, I succeeded in 
devising a method of carrying into practicable effect the 
mathematical principles of that paper, and as a result the 
light compass card with small needles and radial supports 
of both needles and card described in my specification, 
No. 1339, 1876, has come to be very extensively used 
in the Royal Navy, and in nearly all the other navies in 
the world, as well as in the mercantile marine. 

Thirty-five years prior to my mathematical investiga 
tion, the late Astronomer - Royal, Sir George Biddell 
Airy, had shown how the errors of the compass, depend 
ing on the influence experienced from the iron of the 


ship, may be perfectly corrected by magnets and soft 
iron placed in the neighbourhood of the binnacle. 

Although up to the year 1876, when my improved 
compass card came into use, Airy s method for correction 
had never been thoroughly carried into effect, partial 
applications of it had come into general use. There was 
not then, as there had been twenty years previously, the 
question between the advocates of correctors and the 
advocates of no correctors. The absolute necessity for 
magnetic correctors, to make the compass a practically 
working instrument of navigation, had, by the increased 
quantity of iron used in the construction of modern ships, 
been forced upon even the most extreme advocates of the 
system of no correction. The only question was how 
the correction could be effected in the best manner for 
practical purposes. The chief drawback to the perfect 
application of the Astronomer-Royal s method had been 
the great size of the needles in the ordinary compass, 
which renders one important part of his correction the 
correction of the quadrantal error for all latitudes, by 
masses of soft iron placed on two sides of the binnacles 
practically unattainable, and which limits and sometimes 
partially vitiates the other part of the correction, or that 
which is performed by means of magnets placed in the 
neighbourhood of the compass. I therefore endeavoured 
to make a mariner s compass with much smaller needles 
than those previously in use ; but it was only after several 
years of very varied trials that I succeeded in producing 
a compass with all the qualities which I found to be 
necessary for thoroughly satisfactory working at sea, in 
all weathers, and in every class of ship. One result at 
which I arrived, partly by lengthened trials at sea in my 
own yacht, and partly by dynamical theory, analogous 
to that of Froude with reference to the rolling of ships, 
was that steadiness of the compass at sea was to be 
obtained not by heaviness of needles or of compass card, 
or of added weights, but by longness of vibrational period 
of the compass, however this longness is obtained. By 
the term vibrational period, or the period (as it may be 



called for brevity) of a compass, I mean the time the 
compass card with its needles takes to perform a complete 
vibration to and fro, when deflected horizontally through 
any angle not exceeding 30 or 40, and left to itself to 
vibrate freely. Thus, if the addition of weight to the 
compass card improves it in respect to steadiness at sea, 
it is not because of the additional friction on the bearing 
point that this improvement is obtained ; on the contrary, 
dulness of the bearing point, or too much weight upon 
it, renders the compass less steady at sea, and, at the 
same time, less decided in showing changes of the ship s 
head than it would be were the point perfectly fine and 
frictionless, supposing for the moment this to be possible. 
It is by increasing the vibrational period that the addition 
of weight gives steadiness to the compass, while, on the 
other hand, the increase of friction on the bearing point 
is both injurious in respect to steadiness, and detrimental 
in blunting or breaking it down, and boring into the cap, 
and so producing sluggishness after a short time at sea. 
If weight were to be added to produce steadiness, the 
place to add it would be at the very circumference of 
the card. The conclusion at which I arrived was that 
no weight is in any case to be added beyond that which 
is necessary for supporting the card, and that with small 
enough needles to admit of the complete application of 
the Astronomer-Royal s principles of correction. The 
length of period required for steadiness at sea is to be 
obtained without sacrificing freedom from frictional error, 
by giving a large diameter to the compass card, and by 
throwing to its outer edge as nearly as possible the whole 
mass of rigid material which it must have to support it. 

In the compass set forth in my specification No. 1339, 
1876, these qualities are attained by supporting the outer 
edge of the card on a thin rim of aluminium, and its inner 
parts on a series of spokes or radial threads stretched from 
the rim to a small central boss of aluminium, spokes, as it 
were, of a wheel. The card itself is of thin strong paper, 
and all the central parts of it are cut away, leaving only 
enough of it to show conveniently the points and degree 


divisions of the compass. The central boss consists of a 
thin disc of aluminium, with a hole in its centre, which 
rests on the projecting lip of a small aluminium inverted 
cup mounted with a sapphire cap, which rests on a fixed 
iridium point. The weight of the central boss aluminium 
cap amounts in all to about five grains. It need not be 
more for a 24-inch than for a ro-inch compass. For the 
lo-inch compass the whole weight on the iridium point, 
including rim, card, silk thread, central boss, and needles, 
is about 1 80 grains. The limit to the diameter of the 
card depends upon the quantity of soft iron that can be 
introduced without inconvenient cumbrousness on the two 
sides of the binnacle to correct the quadrantal error. 

With the small needles of my new compass, the com 
plete practicable application of the Astronomer -Royal s 
principles of correction is easy and sure ; that is to say, 
correctors can be applied so that the compass shall point 
correctly on all points, and these correctors can be easily 
and surely adjusted at sea, from time to time, so as to 
correct the smallest discoverable error growing up, whether 
through change of the ship s magnetism, or of the mag 
netism induced by the earth, according to the changing 
position of the ship. 

In 1876 he endeavoured to interest the aged 
Astronomer- Royal in his invention, and sent him a 
compass, followed by the accompanying letter : 

March 3, 1876. 

MY DEAR SIR GEORGE I thought you would be inter 
ested in my new compass. The objects I had in view were 
steadiness of indication at sea, and suitableness for the 
application of your method of correcting in all its com 
pleteness. Your description of an accurate method of 
finding the amount with direction of the permanent 
magnetic force has not, so far as I know, hitherto been 
realized, even in experimental arrangements on board 
ship. This I propose to carry out in connection with my 
new compass and the apparatus you saw ; it is nearly 



complete, though it was not attached to the rough illus 
trative instrument which I sent to you on Saturday. 

If you had allowed the instrument to remain at the 
Observatory I should have called on Monday, and explained 
all parts of my plan. The main points are : 1st, Needles 
so small that the distances of their different parts from the 
nearest parts of the soft-iron correctors differ by amounts 
which may be neglected as infinitely small in comparison 
with the distances themselves. 2nd, Soft-iron correctors 
so small that the distances of their different parts from the 
permanent magnet correctors may be regarded as infinitely 
small in comparison with the whole distance. 3rd, 
Accurately graduated adjustment of the permanent cor 
recting magnets. 

The monstrous size of the needles used in modern 
great merchant steamers would require tons (I might say 
hundreds of tons) of soft iron, to fulfil conditions above, 
with sufficient accuracy to give a good practical result for 
your correction for the quadrantal error. 

It is fortunate that the very small needles which I 
have introduced for the sake of conditions I and 2 have 
also a very great advantage in respect to the mechanical 
qualities of the compass over any make of larger size. 
The compass I sent to you is an illustration of what I 
propose for a standard compass. It is read with great 
ease to a quarter of a degree, which is a good deal closer 
than is required or can be usefully practised at sea. 

I gain greatly in mechanical quality, of course, by doing 
away with the fly card, and (at all events for a standard 
compass) this without any sacrifice of convenience. I 
intend to give my compass a thorough trial at sea. Shall 
I let you see it when complete before trial at sea ? I 
shall also, if you desire it, give you a complete statement 
of the details of observation by which I propose to find 
the data required for varying the adjustment of the 
magnets so as to keep the compass correct at all points. 
Believe me, yours truly, 

Sir George Airy. 


The compass was sent by the hand of the late 
Mr. J. Munro, one of his pupils, who tells of its 
reception : 

One day, I remember, Sir William Thomson desired 
me to take his new compass to Sir George Airy at the 
Royal Observatory, Greenwich Park, and ask him what 
he thought of it. A crude, experimental instrument, 
mounted on gimbals in a wooden box, it nevertheless con 
tained the essential features of the improvement ; and 
after I presented it to Sir George, he looked intently at it 
for some time, apparently in deep thought, and simply 
said, " It won t do." When I returned to Sir William, 
and told him of this verdict, he ejaculated, with a trace 
of contempt, " So much for the Astronomer - Royal s 
opinion ! " 

One objection urged by the Admiralty officials 
against his compass was that the permanent magnets 
were not fixed, but required to be adjusted in posi 
tion. He pointed out in reply that the supposed 
permanent magnetism of the ship, which they were 
designed to correct, was itself subject to change. 
And he told how, on H.M.S. Thunderer, in August 
1877, when H.R.H. the Prince of Wales (now our 
King) visited her to watch gun practice, the firing 
of the guns was found to derange her standard com 
pass, demonstrating the necessity for means of 
adjustment of the correcting magnets. 

Time and again did Sir William bring before the 
scientific world, and before nautical men, his improve 
ments. They were praised, they were criticised, 
they were condemned by the prejudiced, but they 
were received with deadly apathy by the Tapers 
and Tadpoles of official circles. At the British 



Association of 1876 at Glasgow he read a paper on 
" Compass-correction in Iron Ships." In April 1877 
he addressed the Institution of Engineers in Scotland 
on Compass-adjustment on the Clyde." At the 
British Association the same year he described a 
Marine Azimuth Mirror for use with his compass, 
and gave another communication on the mariner s 
compass, with correctors for iron ships. Lord Walter 
Kerr, after trying a borrowed compass on H.M.S. 
Minotaur^ wrote in September that he had suggested 
to the Government to purchase it. Gradually the 
shipowners began to realize the advantages of the 
new compass as the captains of the vessels on which 
they had been tried sent in favourable reports. Even 
foreign Governments began to give them a trial. 
Still the British Admiralty proved impervious. In 
1878 Sir William Thomson addressed to the then 
First Lord, the Rt. Hon. W. H. Smith, M.P., the 

following letter : 

April ii, 1878. 

SIR I take the liberty of calling your attention to my 
compass and sounding machine, and asking you kindly to 
consider the question of introducing them into the Royal 
Navy for practical use. 

The compass has been now amply tested at sea in up 
wards of 60 large iron steamers and sailing ships. 1 After 
eighteen months of very varied experience in all seas and 
all weathers it has, as the accompanying printed reports 
show, been found to work well, and to possess some con 
siderable advantages over the other forms of compass 
hitherto in use. After six months trial on board the 
German ironclad Deutschland, a second has been ordered 
by the German Imperial Admiralty, who have also recently 

1 I enclose a list. 


ordered two more sounding machines after a short trial of 
a first one. The Russian Admiralty have recently ordered 
both compass and sounding machine. The compass has 
also been supplied to the Italian Navy and to the Brazilian 
ironclad Independenzia (now H.M.S. Neptune}. 

From results of trials on board ships of war firing 
heavy guns I have recently made some improvements 
in my compass, by which I hope it will be rendered 
thoroughly available for the navigation of a ship of war 
in action, and will so have a great advantage over the 
compasses hitherto in use. My compass on board H.M.S. 
Minotaur is not provided with these improvements, as the 
experience on which they are founded has been acquired 
since the time when it was purchased by the Admiralty, 
but if its action under gun-fire is not found altogether 
satisfactory it will be easy to add them to it without 
disturbing its adjustment on board. 

I venture to suggest that more extensive trials of my 
compass in the Navy might now properly be made, and 
particularly that it should be tried in ships of several 
different classes both as an azimuth compass for ordinary 
navigation and as a between-decks steering compass for 
use in action. 

The enclosed printed reports regarding my sounding 
machine leave no doubt as to its general usefulness for 
ships of all classes, and from them it may be seen that in 
ships of war in trying circumstances it might be of vital 
importance. You will not, therefore, I trust think me too 
sanguine in expressing the hope that the British Admiralty 
will early resolve to have it adopted for general use in the 
Royal Navy. Your ob 1 serv - WILLIAM THOMSON. 

The First Lord s reply was non-committal, but a 
year later Thomson made a proposal to put one of 
his compasses at the disposal of the Admiralty for 
trial at his own expense. This offer produced the 
following response : 



ADMIRALTY, S.W., 23 May 1879. 

SIR With reference to your letter of the 3Oth ultimo, 
I am commanded by my Lords Commissioners of the 
Admiralty to inform you that your offer to supply one of 
your improved compasses at your own expense for trial 
in any ship or ships in which their Lordships may give 
orders to have it tried, and to allow it to remain on trial 
without charge as long as they may desire, is accepted. 

2. I am further to acquaint you that the first suitable 
opportunity for a trial of this machine will be taken 
advantage of, and a further communication will be made 
to you on the subject. I am, Sir, your obedient servant, 

Sir William Thomson, 

The University, Glasgow. 

As, however, Sir William in his summer cruises 
on his yacht made the acquaintance of influential 
naval officers, there arose gradually a movement 
within the Navy for the adoption of the compass. 
Amongst those who warmly advocated the Thomson 
compass, and indeed became its champion against 
the official party who opposed its introduction, was 
Captain Fisher (now Admiral of the Fleet Lord 
Fisher). When H.M.S. Wye grounded in the Red 
Sea the court-martial declared that this would not 
have occurred had she been fitted with Thomson s 
compass and sounding machine. One of the cap 
tains, writing of this to Thomson, declared that in 
advocating his inventions at headquarters they had 
to approach the subject like burglars approaching 
a safe. 

Twice Sir William brought his compass before 
the Royal United Service Institution, on February 4, 



1878, and again on May 10, 1880. On the second 
occasion he described certain mechanical improve 
ments for combating unsteadiness due to vibrations 
caused by the ship s engines ; a device for ascertain 
ing the heeling error ; and improved adjustments 
of the correcting magnets in the binnacle. In the 
discussion which followed Thomson referred to a 
trial of his instrument on the Glatton in 1878, when 
it had remained perfectly steady during gun-fire. 
It was now on trial on the Northampton by order 
of the Admiralty. 

At the bombardment of Alexandria on July n, 
1882, were two ships, H.M.S. Inflexible and H.M.S. 
Alexandra^ that had been fitted with Thomson s 
compass. Captain (afterwards Admiral Sir Charles 
F.) Hotham, who commanded the latter ship, reported 
the superiority of Thomson s compass over other 
patterns, while Captain Fisher (now Admiral of the 
Fleet Lord Fisher), of the Inflexible, stated that 
during the bombardment this compass was particu 
larly useful for steering a course, as it was the 
only compass that would stand the tremendous 
concussion caused by firing the eighty-ton guns. 
He reported it far superior to any other compass 
both with regard to its steadiness and general 
reliability, and had had perfect satisfaction with 
it also on board H.M.S. Northampton. 

It was, however, not until November 1889 that 
the then superintendent of the Compass Depart 
ment of the Admiralty, Captain E. W. Creak, 
F.R.S., could write to Sir William that he had 



received official intimation that his ic-inch compass 
was to be adopted in future as the standard compass 
for the Navy, and that it was to be at once placed 
on twenty ships. 


The standard form of Thomson s compass, as 
adopted by the Admiralty in 1889, is depicted in the 
accompanying figure. Eight small needles of thin 
steel wire from 3^ to 2 inches long, weighing in all 
54 grains, are fixed (like the steps of a rope-ladder), 
on two parallel silk threads, and slung from a light 


aluminium circular rim of 10 inches diameter by 
four silk threads, through eyes in the four ends of 
the outer pair of needles. The entire weight is 
about 170 grains. It has double the period and 
one-seventeenth of the weight of the lo-inch com 
pass previously in common use, and its frictional 
error is not more than one-quarter of a degree. 

The following more recent letter to Admiral 
of the Fleet Lord Fisher deals with the modern 
method of adjustment without the labour of " swing 
ing " the ship : 

GLASGOW, March 3/92. 

DEAR FISHER In answer to your question I enclose 
a paper giving some details as to 50 ships in which the 
compass adjustment has been performed solely by means 
of the deflector. 1 This was 50 out of 180, the adjust 
ment having been done by sights in the other 130 of that 
set. The proportion 50 out of 180 is, I should think, 
pretty nearly our average for deflector. Ships supplied 
with my compass are generally adjusted under weigh in 
any convenient place where there is sufficient sea room. 
In such places it is rarely the case that we have objects 
on shore of known bearings available for the adjust 
ment. So, unless we get the sun, we always adjust by 
deflector ; and if the sun fails during an adjustment, we 
finish it by the deflector. The adjustment by deflector 
is quite thoroughly as trustworthy as by sights of the sun 
or by shore bearings ; and a ship never waits for sights 
after her compasses have been adjusted by deflector. In 
many cases, however, after the adjustment has been com 
pleted by deflector, bearings of the sun have been got, 
and the ship swung to verify the adjustment on all points. 
An error of i on some of the courses may be found ; but 
for all practical purposes the compass is found correct 

1 The deflector and the azimuth mirror are described in Popular Lectures* 
iii. p. 322 and p. 329. 



Residual magnetism and magnetic sluggishness affect ad 
justment by sights quite as much as by deflector. All sizes 
and classes of ships are adjusted by the deflector, includ 
ing large passenger steamers of the P. & O., of American 
lines, Cape mail ships, and cargo steamers, and yachts. 
The adjustment is done by day or night indifferently, in 
fog and in clear weather, or in a gale of wind or rain or 
snow, according as circumstances require; and immense 
savings of money are made for the shipowners and builders 
by avoidance of otherwise unnecessary detentions. The 
benefit to our Navy from the use of the deflector would 
be relatively much greater if the time ever came when 
it should be engaged in large action of war. However 
battered a ship may be, or however suddenly required out 
of port after repairs, an hour and a half would always 
quite suffice to make quite sure of her compass. A ship 
with us is never detained on account of weather for the 
adjustment of her compasses. Yours very truly, 


P. S. Our adjustments here are generally done by a 
compass adjuster, who learned from Mr. W. Bottomley and 
myself in the course of a few days. A week s instruction 
and practice is quite enough to allow any capable adjuster 
to adjust by deflector in a thoroughly trustworthy manner. 
No navigating officer in the Navy would be unable to 
learn thoroughly in a few days ; and, once learned, its use 
would let him always in any part of the world correct his 
compass with perfect confidence. 

From the first, Lord Kelvin s compasses were 
manufactured by the firm of James White, Optician, 
of Glasgow, in which business he became the leading 
partner. As subsequent improvements were made 
in detail further patents were taken out to protect 
the invention. This, however, did not prevent 
imitations more or less close in design from being 
put on the market by rival firms of compass makers, 

7 i8 



involving the vexations of legal proceedings to protect 
the patent rights. In the principal action, Thomson v. 

Moore, his fundamental 
patent was triumphantly 

Plate XII. depicts 
Lord Kelvin standing 
beside his latest compass. 
In this portrait he is 
actually taking a bearing 
by means of the azimuth 
mirror, and is shading 
the side light with his 
hand so as to get a read 
ing of the scale. In the 
accompanying illustra 
tion is shown the form 
of the compass, with the 
two soft -iron corrector 
globes placed one on 
each side at the level of 
the card, and with light 
ing by an electric lamp beneath the compass bowl. 

In recent years the Admiralty has shown pre 
ference for another sort of compass in which the 
whole card floats in liquid, and for ships of war it 
began to supersede Lord Kelvin s form after the 
end of 1906 ; the principles of correction remain, 
however, the same. 

BINNACLE. External View. 



To the Society of Telegraph Engineers in April 
1874, Sir William Thomson communicated a paper 
on " Deep-Sea Sounding by Pianofore Wire," in 
which he described his first success on board the 
Lalla Rookh in June 1872, when he sounded to a 
depth of 2700 fathoms with a 3O-pound sinker hung 
from a three-mile line made up of lengths of piano 
forte steel wire spliced together. He recounted 
further soundings made on the Hooper in 1873 off 
the east and north coasts of Brazil by the same 
simple means, and described the device of an 
auxiliary hauling-in wheel which took off the chief 
strain from the sounding wheel, which must itself 
be very light. He pointed out the advantage pre 
sented by this plan over the old method of sounding 
with a hempen rope, its more rapid operation, its 
compactness, but, above all, the fact that it may be 
used for flying soundings, since in its use it is not 
necessary that the ship be stopped. 

On November n, 1875, Sir William delivered a 
public lecture 1 on Navigation" in the City Hall 
at Glasgow. In this lecture he described various 
nautical instruments, his own deep - sea sounding 
apparatus, and Napier s pressure - log. He said 
little about his compass, but spoke of methods of 
navigation, and of the use of the globes. Referring 
to a terrestrial globe on the platform, he told his 

1 Published 1876 by W. Collins and Co. under the auspices of the Glasgow 
Science Lectures Association. Reprinted in Popular Lectures and Addresses, 
vol. iii. p. i. 




audience that he had registered a vow to lose no 
opportunity of speaking against the neglect of the 
Use of the Globes. A celestial and a terrestrial 


A, Rim holding wire coil. 
C, Clamp for rim. 

B, Winding drum. 

G, Sinker enclosing gauge. 

globe ought to be found in every school of every 
class. The pressure-log, an ingenious device for 
indicating the speed of a ship by causing the rush 
of water against the stern to force up a column of 


liquid in a tube, occupied attention for several years, 
and was the subject of lengthy correspondence 
between Thomson and Wm. Fronde down to the 
end of 1878. 

A sounding machine was put on board the 
Cunarder Riissia in the summer of 1876, when 
Sir William was on his way to the Centennial 
Exhibition at Philadelphia, and he took flying 
soundings while going at 14 knots, and found 
bottom in 68 fathoms, quite unexpectedly in a place 
where 1900 fathoms were marked on the chart. At 
the British Association meeting the same autumn 
he expressed his opinion that the old system of 
sounding by hemp ropes had done its last work on 
board the Challenger. 

In connection with this use of steel wire the 
story is told that Joule, visiting White s shop, found 
Sir William surrounded by coils of wire which he 
was inspecting, and inquiring their use was told 
they were pianoforte wire for sounding. " For 
sounding what note?" inquired Joule. "The deep 
C," was Sir William s reply. 

Nevertheless, officialdom remained unconvinced 
and apathetic. In lectures to the United Service 
Institution in 1880, 1881, and 1884, he still con 
tinued to advocate the sounding machine and the 
compass, and in the end his persistency won the 
day. A letter which he addressed to Captain 
Wharton (afterwards Sir William J. L. Wharton, 
Admiral and Hydrographer) is a contribution to 


Nov. 26/88. 

DEAR CAPTAIN WHARTON I send by book post, 
along with this, a volume of the Society of Telegraph 
Engineers Journal, in which you will see on p. 207 de 
tails including latitude and longitude of my first piano 
forte wire sounding. 

On page 218 you will see some evidence of how anxious 
I was to give freely all the assistance I could to the 
Admiralty in respect to the deep-sea survey soundings. 
And on pages 223-228 you will see that I was also 
anxious to make known to the public the possible use of 
steel wire for flying soundings in ordinary navigation. 
My letter to The Times in May 1875 about that time, 
on the loss of the Schiller on the Scilly Islands, was 
another attempt to get the public to accept my naviga 
tional soundings gratis. When I saw nothing come of 
all this, I commenced a voyage to New York and back 
in the summer of 1876, making a serious effort to realise 
the thing for practical use myself, and at the end of 1876 
I took my first sounding-machine patent. But you see 
from my beginning in June 1872, of which I wrote a 
particular account to the Hydrographer (Sir George 
Richards) in July, I all along for more than four years 
showed my hand and kept back nothing, in letters and 
in conversation and publications, both to the Admiralty 
and general public ; and ultimately I was obliged to take 
a patent and work the thing out myself if the public was 
to get the benefit of it at all. 

The enclosed little article from the Phil. Mag. for Nov. 
i 874 shows that I began similarly in respect to the compass. 
From that time till the end of the summer of 1875 I tried, 
on shore and afloat, to realize the desideratum described 
in the marked passages at the end of the article, and showed 
everything I was doing, from time to time, to Sir Frederick 
Evans. I was most anxious that the Admiralty should 
take it up, and I should have been most pleased to help 
freely in any way possible, and to work hard to bring about 
the result. I could not succeed in getting the slightest 
encouragement, or in raising any interest whatever in the 





subject ; and at last in despair I resolved, about the end 
of 1875, to work it out myself and take a patent. 

Forgive this long yarn, but I thought you might like 
to know that I have from the very first been always most 
anxious to do anything I possibly can in perfect unison 
with the Hydrographic Office. Believe me, yours very 

An important feature of the sound 
ing machine was the dynamometric brake 
applied to the paying-out wheel, to regu 
late the movement ; it had first been 
patented by Thomson in 1858 as an 
adjunct to machinery for laying sub 
marine cables. The first form of depth- 
recorder attached to the sinker con 
sisted of a glass tube closed at the top, 
containing air which was compressed as 
the water rose in it higher and higher 
under the increasing pressure ; the 
amount of compression being registered 
by the use of chemicals, ferroprussiates 
at first, chromate of silver later, giving 
indications by change of colour. In the 
final form of depth-recorder the degree 
of compression was indicated by a piston 
which was forced into a cylinder con 
taining air, and a marker pushed along 
the piston recorded the depth mechani 

Lord Kelvin used often to tell how 
in August 1877, returning from Madeira 
in the Lalla Rookh in thick weather, he steered by 


C, Marker. 

D, Piston. 


soundings taken every hour, right up to the Needles, 
having no sight of land except just a glimpse of the 
high cliffs east of Portland. 

Writing in December 1892 to Captain Lecky, 
Lord Kelvin remarks : 

What a sad disaster that was, of the Roumania. If 
they had used my sounding machine to get bottom when 
they came within I oo fathoms, and then kept it going once 
every half-hour, they never would have come into danger. 
On all those coasts (Finisterre to Cape St. Vincent) the 
danger line is outside 50 fathoms, and safety is to be had 
by keeping the machine going (two men at it) once an 
hour, or once every half-hour, or more frequently when 
circumstances require it. It is wonderful how slow ship 
owners and ship-insurers, not to say ship-officers, are to 
see that they must not only have the machine on board, 
but must use it systematically, and that if they do so, 
such an accident as stranding on any of our European 
coasts, whether outside, on the Atlantic, or in the English 
or Irish Channels, or in the North Sea, could never happen 
to a non-disabled ship. 

When the battleship Montagiie was lost in 1906 
on Lundy Island, he was even more emphatic in 
denouncing the folly of captains who neglect such 
simple means of safety. 


The furnishing of lighthouses with distinctive 
lights that should prevent them from being mis 
taken one for another was a matter of keen interest 
to Sir William Thomson during these years. 
Flashing and revolving lights were indeed known ; 
and some attempt had been made to give them a 


distinctive character by assigning to them slower or 
quicker periods of revolution. His principal contri 
butions to the subject are to be found in an article on 
" Lighthouses of the Future " in Good Words, March 
1873 ; a lecture on the Distinction of Lighthouses, 
delivered on October 24, 1877, to the Shipmasters 
Society, reported in The Times, October 31 ; and 
a paper on " Lighthouse Characteristics," read at 
the Naval and Marine Exhibition at Glasgow, 
February n, 1881, read also and discussed at the 
Society of Arts, March 2, 1881, and reprinted in 
Vol. II. of his Popular Lectures and Addresses. 
In the first of these he drew attention to Babbage s 
suggestion of 1851 of an occulting light, and Captain 
Colomb s system of signalling by flashlights in the 
Navy, introduced about 1867. He now proposed 
that lighthouses should flash out, in short and long 
flashes, that is, in dots and dashes, some distinctive 
letter of the Morse code. The letter to Prof. 
Peirce (p. 659 above) gives a history of his efforts. 
The following letter, addressed to Dr. John Hopkin- 
son, defines his plan : 

Jany. 2oth, 75. 

DEAR HOPKINSON I have only this moment fallen 
upon a paper on group-flashing lights which you had 
kindly sent me, possibly during my absence in summer. 
I see on page 4 a mistake which I am sure you will 
gladly know to be a mistake. You say that the scheme 
proposed by myself has not received any practical recog 
nition. It has been in action on the Holywood Bank 
Lighthouse since the first of Nov. The signal there 
adopted is two short eclipses and a long, making the 


letter U (dot, dot, dash) of the Morse alphabet. It is 
exceedingly well liked by the pilots and other practical 
men who have had experience of it. 

Since the time of our last correspondence I have 
modified my plan from short and long flashes to short 
and long fixed lights. 

I have also a very simple and durable mechanism for 
producing the same kind of distinction by longer and 
shorter extinction of gas. I have this going for the sake 
of illustration in my lecture room for several hours every 
evening at a window whence it is visible to a considerable 
part of Glasgow. It is probable it will soon be applied 
to the Cumbrae Light, Claugh Lighthouse, and a new 
lighthouse to be made on the Clyde on Roseneath patch. 
I do hope you will endeavour to move the Trinity Board 
to look into my proposal. If they will do so I feel per 
fectly confident that they will adopt it. You will see 
that it is very much simpler than the group -flashing 
lights which form the subject of your paper. 

I am quite aware, however, of the value of the system 
of horizontal condensation used in the ordinary revolving 
lights and in the group-flashing lights. So of course I 
don t want to urge that they should be given up in every 
case. The great power of the ordinary revolving light 
will no doubt secure its being always used at some of the 
eclipses. My present proposal is to apply to every light 
which is at present a fixed white light, a simple eclipsing 
apparatus which shall make one, two, or three eclipses, 
each eclipse to be for a certain duration, about half a 
second, or three times as long as that for the dash, and the 
successive eclipses of the signal are to be separated by 
half a second interval. The light is to burn brightly and 
undisturbed for five or six seconds, then is to follow the 
successive eclipses distinguishing it, then the light is to 
burn brightly for five or six seconds again, and so on 

The Holywood Bank Light was a fixed oil light 
distinguished by a red shade. The red shade is now 
removed, and the eclipses are made in an exceedingly 


simple manner by a revolving ring carrying screens. 
Nothing can possibly be more simple than the mechanism, 
or more easy to apprehend than the result. It can never 
be then for the reason you stated that my plan shall be 
not applied to every one of the present most important 
kinds of lighthouses. To promote its usefulness, however, 
it is absolutely essential that the period be diminished to 
a small fraction of what it ordinarily is. This has now, 
I am happy to say, been done for the Toward Point 
Light, in accordance with my recommendation. The 
period was as usual about a minute. It is now about 
ten seconds. Any one who has looked for one of the 
ordinary revolving lights at sea, will agree with me as to 
the painfully unsatisfactory character of the fifty seconds 
(or longer) waiting for a flash and the chance of missing 
it altogether, when it does come. A revolving light of a 
minute or of a longer period is in point of fact much less 
easily " picked up " in all circumstances of difficulty, 
particularly in bad weather, rainy and stormy, than a 
fixed light of much smaller intensity. 

In his lecture of 1877 Sir William advocated the 
superiority of distinctions made by intermittent 
flashes, or by revolving beams of light rather than 
by colours, which might be deceptive in fog. He 
instanced his own Craigmoor Light in the Firth of 
Clyde, which flashed with a twice -repeated long- 
short signal, or , which was, in fact, the 
telegraphic letter C. Also the Holywood Bank 
Light at Belfast Lough, which gave (that is, 
dot, dot, dash) as its signal. In the 1881 lecture he 
classified the characteristic qualities of all light 
houses under three heads : Flashing Lights, Fixed 
Lights, and Occulting or Eclipsing Lights. He 
pointed out that a fixed light may be mistaken for 
a masthead light of a steamer ; that the Admiralty 


List for 1875 gives about 100 flashing lights around 
the British Islands, all alike except in that they 
vary in duration from one flash in four seconds to 
one flash in two minutes. A new and important 
departure had been made in 1875 by the intro 
duction by Dr. John Hopkinson of a group-flashing 
light on the Royal Sovereign shoal, giving successive 
groups of flashes, with three flashes in each group. 
But three dots was simply letter S of the Morse 
code. On this Sir William expressed the hope 
that the ignorance of the Morse code by sailors 1 
would prove no obstacle. "The great thing," he 
said, " is to find how lights may be most surely and 
inexpressively rendered distinctive, so that no sailor, 
educated or uneducated, highly intelligent or only 
intelligent enough to sail a collier through gales 
and snowstorms and fogs all winter, between New 
castle and Plymouth, may know each light as soon 
as he sees it without doubt or hesitation." Then 
he turned to statistics, and noting that, of the 623 
lights in the British list, 490 were fixed, 112 flashing, 
and 21 occulting or eclipsing, he urged that the 
superior apparent brilliancy of a flashing light was 
dearly bought because of the great diminution of 
usefulness to the sailor in the intervening periods 
of darkness. What was gained in brilliancy was 
lost in time of visibility. He, therefore, advocated 

1 " Sailors, we may hope, are happily ignorant of this truth, otherwise the 
proverbial captain of the collier would be calling out to his chief officer, 
Bill, was that a S, or a I, or a H, or a E ? Bill, if he was well up in 
dramatic literature, would reply, Captain, them is things as no fellow can 
understand. " 

xvn TIDES 729 

long periods of illumination broken up by short 
groups of eclipses or occultations on some character 
istic plan. He had himself erected on the college 
tower of the University of Glasgow a trial eclipsing 
light giving the signal (dot, dash, dot), or 
letter R of the Morse code, by eclipses ; the group 
lasting seven seconds, with thirteen seconds of un 
interrupted light between. Finally, he advocated 
the adoption of similar group signals for the sounding 
of sirens. 

During the summer of 1880 he had much corre 
spondence with the Commissioners of Irish Lights, 
the authorities of Trinity House, and the Clyde 
Commissioners, in which he urged the adoption of 
distinctive characteristics on this plan. 


Tidal phenomena often occupied Lord Kelvin, 
and he gave much thought to their elucidation. 
Perhaps the best account of his work on them is 
that to be found in the lecture which he delivered 
at Southampton in 1882, reprinted in Vol. III. of 
his Popular Lectures. He carefully pointed out the 
distinction between waves due to the action of wind, 
sudden " tidal waves " caused by earthquakes, and 
true tides due to the attraction of the sun and moon. 
He also discovered, from the reduction of tidal 
observations, a great swell of the ocean from one 
hemisphere to the other and back again, once a year, 
and explained it as the result of the sun s heat. He 
attached great importance to systematic measurement 



of the rise and fall of the sea at different ports ; 
and himself devised a form of Tide-gauge of 
great simplicity. The theory of the tides had been 
worked out many years before by Laplace and Airy, 
who had shown that if the seemingly irregular 
variations of rise and fall were observed at any port 
for a considerable time, the observations could be 
reduced or analysed by very elaborate mathematical 
calculations into a number of constituent tides ; and, 
if these have been found, it is possible to predict the 
height of the tide at any future time, for the same 
place, by computing the separate constituents and 
adding them together. Down to about 1876 the 
only means of analysing the various components 
which go to make up the complicated variations of 
rise and fall was a very laborious arithmetical process 
of harmonic analysis. This was investigated and 
carried out from 1867 onwards by a Tidal Com 
mittee of the British Association, formed at Sir 
William s instigation, and by the Indian Govern 
ment for various ports in India. But in 1876 Sir 
William Thomson discovered a mechanical means 
of performing this, by the ingenious Tidal Harmonic 
Analyser, in which use was made of James Thom 
son s disk-globe-cylinder integrator, mentioned on 
p. 692. The first working model had five of the 
disk - globe - cylinders, and served for finding the 
terms of first and second orders only of the harmonic 
series. A larger instrument is used at the Meteoro 
logical Office. Besides these a synthetic instrument 
for use as a Tide - Predicter (now in use at the 


National Physical Laboratory) was constructed, in 
which the various periodic components of rise and 
fall, as observed by the Gauge, and computed 
by the Harmonic Analyser, could, by an ingenious 
mechanism, be recombined for any future epoch. 
The entire tides of any port can be predicted by 
means of the instrument, which in twenty - four 
minutes draws the curve showing the rise and fall 
for a whole year to come. In 1876 Sir William 
showed the first model of this instrument, at the 
Exhibition of Scientific Apparatus at South Ken 
sington, to Queen Victoria. The best account of 
this series of instruments is to be found in the 
Proceedings of the Institution of Civil Engineers, 
vol. Ixv., March i, 1881, together with the discus 
sion which arose on the paper, and Sir William s 
reply to the pretensions of a claimant to the in 
vention of the Predicter. 

On several different occasions Lord Kelvin 
took an important part in committees to advise the 


Early in September 1870 the public was shocked 
by the news that H.M.S. Captain, a newly-built 
turret ship of 6950 tons, with engines of 900 H.P., 
while on her experimental cruise, was caught in a 
gale in Vigo Bay, and went down with all hands, 
there being about 500 persons on board, including 
her designer, Captain Cowper - Coles. After the 


disaster the Admiralty appointed a Committee to 
examine the designs upon which the Captain and 
other recent ships of war had been constructed. The 
Marquis of Dufferin was chairman, and the majority 
of the Committee consisted of experienced naval 
officers. But a notable departure was made in 
adding to the Committee several leading scientific 
men, including Sir William Thomson, Professor 
Rankine, Mr. W. Froude, and Mr. G. P. Bidder. 
The instructions to the Committee on their appoint 
ment in January 1871, stated that the Admiralty 
sought a professional and scientific opinion upon 
the designs of ships of various types. The inquiry 
touched on the faulty points in the design of the 
Captain, the relative stability and efficiency of the 
Monarch, and the improvements possible in ships 
of other classes. At that date the first-class ships 
still carried masts and sails, and one of the con 
tentious points of the inquiry was whether the 
Monarch, a two-turret armour-clad ship carrying 
full sail equipment, could be really efficient as a 
fighting engine if built also to have real efficiency 
under sail. The Committee met fortnightly through 
the spring of 1871, and made its final Report in 
July. Several definite scientific questions were 
remitted to a Scientific Sub - Committee under 
Thomson as chairman. Rankine made a Report 
on the stability of ships under canvas, demonstrat 
ing that the Monarch had a limiting safe angle 
of heeling in a squall of 27^ as compared with 
the 9 of the Captain. Thomson for the Sub- 


Committee drew up a Report on the stability of 
unmasted vessels such as the Thunderer and the 
Devastation, based upon an investigation by Rankine 
and himself in February. He also drew up Reports 
on the stability and structural strength of ships of 
the Cyclops class. The minutes of evidence show 
that Thomson also gave evidence himself upon 
the inclination producible by wind - pressures and 
upon exceptionally steep waves. The work of this 
Commission was very heavy, and its conclusions 
important, as it had to lay down rules to govern the 
construction of future vessels. Even definitions 
and expressions which have since become funda 
mental (e.g. " righting-moment ") originated in the 
course of its work. Sir William used to travel up to 
town every alternate week on Wednesdays, for four 
days absence from his University duties, part of which 
were delegated to James T. Bottomley at this time. 


In December 1904 the Lords Commissioners 
of the Admiralty decided to appoint a Committee 
to review the types of fighting ships which the 
Board of Admiralty proposed to adopt for the 
British Navy. This Committee, presided over by 
Admiral of the Fleet Lord Fisher, comprised seven 
distinguished naval officers, together with seven 
civilian members, of whom Lord Kelvin was one. 
After considering various general questions such 
as size of guns, uniformity of equipment, speed, 


number, spacing and position of guns, the Com 
mittee agreed to an interim report proposing outline 
designs for two special types, a 21 -knot battleship 
carrying ten 1 2-inch guns, and a 25-knot armoured 
cruiser with eight 1 2-inch guns. Lord Kelvin took 
a continuous and energetic interest in all these steps, 
frequently corresponding with the President explain 
ing his views. Amongst the great changes, steam- 
turbines were recommended for propulsion. For 
the details of design sub-committees of the official 
members were formed, the non- official members 
being asked to co-operate in the final conclusions. 
The Committee had before it a large number of 
preliminary designs, from which it selected a smaller 
number for detailed consideration by aid of fuller 
drawings and models. Lord Kelvin put forward 
certain proposals as to the under-water form of hull, 
based upon a suggestion which he had first made 
(p. 751) to the Institution of Mechanical Engineers 
in 1887, for effecting a possible addition to the dis 
placement or carrying power of the ship without 
adding to the wave-resistance or reducing the speed. 
The Hon. C. A. Parsons was called in to counsel as 
to the proposed adoption of turbines. Lord Kelvin 
again took a great personal interest in this question, 
and towards the end of January 1905 further advised 
the Committee as to certain technical difficulties, 
as to arrangements for the compasses and their 
protection, and as to the due provision and proper 
placing of the instruments for control of fire, range, 
and communication of orders. He took a keen 




interest in the operations of the Committee, and his 
scientific knowledge, no less than his experience in 
seamanship, was of distinct value in its delibera 
tions. He was disposed on the whole towards 
favouring the swift armoured cruiser, the Indomitable 
type, rather than the heavier battleship, the Dread 
nought type, but did not dissent from the unanimous 
report of the Committee for the adoption of both 
types. As a result the British Navy found itself 
equipped with the famous Dreadnought (1907), 
and the even more remarkable Indomitable (1908), 
types which are now being fast multiplied in naval 

He also advised the Admiralty Committee on 
Education of Naval Executive Officers in 1885 ; 
and in 1873, at the request of the Plimsoll Parlia 
mentary Committee, he drew up a memorandum on 
the question of insecure navigation. 

The tables for facilitating Sumner s method of 
finding the position of a ship at sea, which Lord 
Kelvin drew up, prove the interest he took in sea 
manship. The present highest authority in the 
British Navy has assured the writer that he con 
siders Lord Kelvin as the man who has done by far 
the most for the advancement of navigation in our 
time. " I don t know," said a sailor in the distant 
seas of the East, " who this Thomson may be, but 
every sailor ought to pray for him every night." 
And the gratitude of the whole world follows him 
for what he did. 



FAMILIAR as are the phenomena of rotating bodies 
in such instances as the fly-wheel and the spinning- 
top, it is surprising how backward has been the 
teaching of the dynamics of rotation. Very few of 
the treatises on mechanics in vogue to-day have 
anything to say about the all-important principle of 
the persistence of the axis of rotation in steady 
motion. Yet it is this persistence which enables 
the spinning-top to stand upright ; which gives the 
rifle- bullet its deadly fixity of direction ; which 
keeps the earth s axis pointing always to the celes 
tial pole. That scientific toy, the gyroscope, a 
heavy top spinning between bearings carried on a 
gimbal ring, will teach more of this subject in an 
hour than pages of disquisition. It became widely 
known in the fifties, after the researches of Fou- 
cault ; but its principle was known and taught at 
Cambridge by Airy and by Earnshaw long before. 
The strange stiffness shown by the spinning disc ; 
the singular way in which its axis sidles off to 
right or left when a force is applied to turn it 
upward or downward ; the seeming determination 




with which it points its axis always in the same 
direction while one walks about or turns oneself 
when carrying it, are all consequences of this prin 
ciple of persistence of axis of spin. 

When still an undergraduate, as narrated on 
p. 79, Lord Kelvin and his friend Hugh Blackburn 
were struck by the problems of rotation, and at the 
time when they were reading together for the great 
mathematical test of the wranglership, they spent 
a week of their seaside reading-party in spinning 
tops and rounded stones picked up on Cromer 
beach. Set up a peg-top on its point, or try to 
stand an egg-shaped stone upon its end unless it 
is spinning it at once falls over. But if it is spin 
ning it will stand up, and will resist being pushed 
over. Nay, if you spin the egg-shaped stone on 
its side, it will of itself rise up and spin on its end. 
Why this acquired stiffness ? Why does a body 
when in rapid movement acquire an apparent power 
of resisting disturbance which when still it does 
not possess ? All through his scientific life Lord 
Kelvin was pursued by importunate problems that 
depend on this apparent stiffness acquired by rotat 
ing bodies in virtue of their rotation. Even at the 
age of fifteen he was familiar with the mathematics 
of rotating bodies, as his Essay on the Figure of 
the Earth (see p. 10) shows ; and Poinsot s theory 
of couples had been brought to his notice by Nichol. 
In 1846 he wrote a mathematical note on the axis 
of rotation of a rigid body (later embodied in 
Thomson and Tait, 282-284). He was therefore 


certainly familiar with d Alembert s theory of pre 
cession. The earth s axis, though in general it 
points in a constant direction, slowly shifts around 
in the course of the centuries, exactly as the axis 
of an obliquely spinning top slowly " precesses " in 
obedience to the downward force of gravity ; though 
in the earth s case it is the action of sun and moon 
upon its bulging equatorial matter which causes 
its axis of rotation to " precess." Thomson, with 
that instinctive faculty that arose from familiarity 
with the thing itself, thought out afresh the theory 
of precessional forces, and refashioned the dynamical 
formulae that express the couples which determine 
the movements of the axis of spinning bodies. To 
aid his thought he devised new forms of spinning- 
tops and gyrostatic models. It was one of these 
which he showed in 1863 to Helmholtz in operation 
with disastrous results to his hat see p. 430. 
The generic name which Thomson gave to these 
most instructive toys was the gyrostat. A gyrostat 
is simply a heavy, well-balanced, finely pivoted fly 
wheel, like the earlier gyroscope, but enclosed in a 
hollow metal box or case, within which it is spun. 
When so enclosed, and suitably mounted, a variety of 
experiments can be shown that are not readily made 
with the older gimbal-mounted form of instrument. 
In one of these forms Thomson mounted the 
gyrostat within a concentric polygonal rim, so that 
it could stand on edge, or skate about on a sheet 
of glass. Others were mounted on stilts, or slung on 
suspensions to afford various degrees of freedom. 



Sundry experiments with them were described in 
Nature on February i, 1877, and are mentioned in a 
long paragraph added to Vol. I. Part I. of Thomson 
and Tait s Treatise, 345, when revised for the 
second edition in 1879. Piazzi Smyth had twenty 
years before proposed the use of a gyroscope to 
steady a platform for astronomical observations on 
board ship ; but Thomson now demonstrated that 
the gyrostat when spinning not only tended to 
preserve an invariable axis of spin, but that in this 
tendency it showed a remarkable quasi-elasticity. 
If a blow were given to its frame, it quivered to 
and fro like a stiff spring, and returned to its own 
position. Thenceforward kinetic stability, the sta 
bility of position due to the reaction of the moving 
mass, became a prominent quality to be investigated; 
and gyrostatic domination, the domination exerted 
upon a system by any revolving masses within it, 
assumed a new importance. A favourite experiment 
shown to visitors in the laboratory was made with an 
enclosed gyrostat, with its axis of rotation vertical, 
pivoted by its case on horizontal trunnion bearings 
to a square frame of wood, by which it could be 
carried about with the frame level. If the experi 
menter holding this in his hands walks in a 
straight line, or turns round in the same direction 
as that in which the fly-wheel is spinning, nothing 
happens ; but should he turn round the other way, 
the gyrostat immediately turns head-over-heels on 
its pivots, as if bewitched. Many other curious 
experiments were shown, in which the gyrostats 


visible or concealed were made to stand balanced 
in strange positions, or nodding their axes while 
sweeping round in precession, thus imitating the 
astronomical phenomenon of nutation. These 
strange effects, all capable of being brought under 
mathematical calculation, had a fascination for Thom 
son, who saturated himself with the study of their 
perverse ways. 

Noting the philosophical bearing which this 
question had upon the physical condition of the 
earth, he constructed liquid gyrostats, ellipsoidal 
metallic shells, both oblate and prolate, filled with 
water. The spinning of the oblate ellipsoid about 
its axis of symmetry was found to be stable that 
of the prolate unstable. A hard-boiled egg, if spun 
on its end, would " sleep " like a top. If spun on 
its side it would rise up and spin on end. But 
an unboiled egg could by no means be induced to 
spin on its end. This was a favourite class illus 
tration. On one occasion a mischievous student 
slipped furtively into the lecture theatre before 
hand, and substituted two fresh eggs for the pair, 
boiled and unboiled, which were provided for the 
lecture. When it came to the moment the con 
spirators waited breathlessly the result of their 
deed. " Neither of them boiled " was Sir William s 
unhesitating verdict, as he tried to spin them. 

Another of Lord Kelvin s tests for an egg is the 
following : Spin the egg on its side. Then lay 
the finger on it for an instant, just to stop it. On 
lifting the finger, if the egg is boiled it remains 



still, if unboiled it goes on turning ; for though the 
shell was stopped the liquid inside was still in 
motion, and moves the shell when the finger is 

In 1875 he gave to the Edinburgh Royal 
Society the theory of the spinning-top to account 
for its rising 1 from the oblique position to the 
vertical attitude in which it " sleeps." His ex 
planation, that this action depended on friction at 
the rounded point of the peg, had been anticipated, 
however, by Jellett in 1872. 

But it was not spinning-tops alone that exhibited 
kinetic rigidity. 

The following story was told by James White, 
the optician, within a day of its occurrence in 1868: 

Thomson had been to Sturrock s, the fashionable 
hairdresser s, in Buchanan Street, Glasgow, some 
two doors from White s shop. At Sturrock s he 
had seen an endless revolving indiarubber rope or 
chain used for driving a rotatory hair-brush. He 
came excitedly into White s shop as soon as he was 
free. " White, come with me." And, without a 
word of explanation, he hurried White to Sturrock s 
and had the endless chain put into motion, and 
showed White, by striking it, the rigidity of form 
which it had acquired in virtue of its motion. 
" There ! get one put up in the class-room at 
College like that, at once ! " and off he went. In 

1 " Hurry on the precession, and the body rises in opposition to gravity " ; 
" delay the precession, and the body falls, as gravity would make it do if it 
were not spinning," were two of Thomson s aphorisms. The effect of friction 
at the peg is to hurry on the precession. 


a few days the chain was put up ; and his senior 
students remembered the delight with which he 
showed it to them, and shortly after to Tait who 
had come over from Edinburgh. He would hit the 
lower end of the loop vigorously with a stick, and 
thus force it into various almost fantastic shapes or 
kinks, which would persist for some minutes. 
Thomson had, of course, long been keen on problems 
of kinetic stability, so the chain appealed to him. He 
devised numerous other experiments on analogous 
cases of the quasi-rigidity of motion. A circular 
disk of thin paper spun rapidly around its centre 
becomes so stiff as to resist a blow of the fist, and 
resounds when struck. Professor Perry, a student 
of Thomson s in the seventies, has described most 
of these phenomena in his admirable lecture l on 

It dawned upon Sir William Thomson that 
in the quasi - rigidity of spinning bodies there 
was a simulation of that property of matter 
known as elasticity, and that it might even be 
possible to explain the phenomena of elasticity 
itself by supposing the molecules, or some of them, 
to be in a state of rotation. He imagined a chain 
of gyrostats all spinning, and connected together 
by links ; and he laid before more than one of the 
learned societies 2 mathematical discussions of the 
properties of a stretched string of gyrostats, along 
which string a wave might be propagated exactly 

1 Published, 1890, by the Society for Promoting Christian Knowledge. 

2 Land. Math. Soc. Proc. vi. p. 190, April 1875 ; Proc. Roy. Soc. Edin. 
<viii. p. 521, April 1875. 



as along a stretched elastic cord. Then it became 
evident that if a revolving fly - wheel could so 
behave, a whirling vortex filament in a frictionless 
fluid would also possess a quasi-elasticity, because it 
is in rotation. Indeed, the rebound which he had 
observed with smoke-rings showed such to be the 
case. Part of his researches on vortex-statics was 
concerned with this idea. Again, the kinetic theory 
of gases, in which the " spring of the air," dis 
covered two centuries before by Robert Boyle, was 
explained as the result of innumerable multitudes 
of free-flying molecules dashing about in space and 
colliding with one another, had been demonstrated 
by Joule, and Clausius, and Maxwell to be pro 
foundly true. If it were true, however, the mole 
cules or atoms must themselves be elastic bodies, 
and not the infinitely hard round objects which 
before they had been regarded. 

In November 1880 Sir William consented to 
give another discourse at the Royal Institution. 
When asked by Dr. De la Rue what the subject 
was to be, he replied : 

MY DEAR SIR The title of my lecture might be 
" On Elasticity viewed as a possible Mode of Motion " 
unless Tyndall has patented the expression, and refuses 
to grant me a license ! Believe me, yours very truly, 


When the discourse was given on March 4, 1881, 
his opening sentence was : 

The mere title of Dr. Tyndall s beautiful Heat, a 
Mode of Motion, is a lesson of truth which has manifested 


far and wide through the world one of the greatest dis 
coveries of modern philosophy. I have always admired 
it ; I have coveted it for Elasticity ; and now by kind 
permission of its inventor, I have borrowed it for this 
evening s discourse. 

He went on to explain that the hypothesis would 
not be raised into a certainty until the elasticity of 
the molecules themselves should have been demon 
strated to be due to motion ; and all he claimed 
now was to point out a possibility. He referred to 
the well-known examples of the elastic-like firmness 
of spinning-tops, of rolling hoops, of bicycles in 
motion, and of smoke-rings and gyrostats. He 
showed how a flexible endless chain of steel links 
running round a revolving pulley, and then 
suddenly caused to jump on to a platform, stood 
up like a hoop and rolled along the platform until 
its motion was lost by impact and friction. Also 
a whirling mass of water in a rotating vase was 
shown to possess a jelly-like stiffness. " May not 
the elasticity of every ultimate atom of matter be 
thus explained ? " he asked ; but checked the 
speculation by adding : " But this kinetic theory 
of matter is a dream, and can be nothing else, until 
it can explain chemical affinity, electricity, mag 
netism, gravitation, and the inertia of masses (that 
is crowds) of vortices." There were difficulties ; 
but he ended optimistically : " Belief that no other 
theory of matter is possible is the only ground for 
anticipating that there is in store for the world 
another beautiful book to be called Elasticity, a 
Mode of Motion." 


Two years later, in a paper given to the Royal 
Society of Edinburgh, he showed, by a mathematical 
investigation of a gyrostatically dominated com 
bination, that any ideal system of material particles, 
acting on one another mutually through massless 
connecting springs, may be perfectly imitated in a 
model consisting of rigid links joined together and 
having rapidly rotating fly-wheels pivoted on some 
or on all of the links. And so he produced out of 
matter possessing rigidity, but absolutely devoid of 
elasticity, a perfect model of a spring-balance. 

Not only this : for he saw also that by gyrostatic 
models he could imitate the phenomena of mag 
netism, and could design even a gyrostatic compass 
which, unlike the magnetic one, should direct itself 
always toward the true north pole of the rotating 
globe of the earth. A favourite experiment was to 
stand a gyrostat obliquely on his finger, place 
another gyrostat on the top of it, slanting at a 
different angle, and a third gyrostat on the top of 
the second, so making a crooked chain of them. Nor 
did he stop here ; for, as we shall see later, he found 
it possible, by joining up gyrostatic elements into a 
network or tissue, to imitate the properties of the 
ether of space in transmitting transversal waves. 

Problems connected with the propagation of 
wave-motion exercised over Thomson s mind a 
never-ending fascination. They appealed to him 
not only by reason of his instinct for mathematical 
analysis and as problems of hydrodynamics, but by 



virtue also of his passion for seamanship and all 
that pertained to the sea. 

In discussing the tides, we have seen how Sir 
William Thomson at the outset distinguished 
between the periodic movements due to the attrac 
tion of the sun and moon, and those generally 
much more rapid due to the driving action of 
wind. He distinguished no less carefully between 
the waves in which the restoring force was the 
weight of the water itself, and those lesser crispa- 
tions in which the restoring force was the surface- 
tension of the water - surface ; for these last he 
termed ripples. The distinction is well brought out 
in a communication on Ripples and Waves, printed 
in Nature, November 2, 1871 ; a result of the 
first-season cruise of the Lalla Rookh (see p. 611). 
The principal passages in it are here reproduced. 

I have often had in my mind the question of waves as 
affected by gravity and cohesion jointly, but have only 
been led to bring it to an issue by a curious phenomenon 
which we noticed at the surface of the water round a 
fishing-line one day, slipping out of Oban (becalmed) at 
about half a mile an hour through the water. 

What we first noticed was an extremely fine and 
numerous set of short waves preceding the solid [the 
line], much longer waves following it right in the rear, and 
oblique waves streaming off in the usual manner at a 
definite angle on each side, into which the waves in front 
and the waves in the rear merged so as to form a beautiful 
and symmetrical pattern, the tactics of which I have not 
been able thoroughly to follow hitherto. The diameter of 
the " solid " (that is to say, the fishing-line) being only two 
or three millimetres, and the longest of the observed waves 
five or six centimetres, it is clear that the waves, at distances 



in any directions from the solid exceeding fifteen or twenty 
centimetres, were sensibly unforced (that is to say, moving 
each as if it were part of an endless series of uniform 
parallel waves undisturbed by any solid). Hence the 
waves seen right in front and right in rear showed (what 
became immediately an obvious result of theory) two 
different wave-lengths with the same velocity of propa 
gation. The speed of the vessel falling off, the waves in 
rear of the fishing-line became shorter and those in 
advance longer, showing another obvious result of theory. 
The speed further diminishing, one set of waves shorten 
and the other lengthen, until they become, as nearly as I 
can distinguish, of the same lengths, and the oblique lines 
of waves in the intervening pattern open out to an obtuse 
angle of nearly two right angles. . . . The speed of the 
solid which gives the uniform system of parallel waves 
before and behind it was clearly an absolute minimum 
wave-velocity, being the limiting velocity to which the 
common velocity of the larger waves in rear and the shorter 
waves in front was reduced by shortening the former and 
lengthening the latter to an equality of wave-length. 

Taking -074 of a gramme weight per centimetre of 
breadth for the cohesive tension of a water-surface, . . . 
I find, for the minimum velocity of propagation of surface 
waves, 23 centimetres per second. . . . 

About three weeks later, being becalmed in the Sound 
of Mull, I had an excellent opportunity, with the assistance 
of Prof. Helmholtz and my brother from Belfast, of deter 
mining by observation the minimum wave velocity with 
some approach to accuracy. . . . [The mean result of 
four determinations gave 23-22 cms. per second ; and 1-7 
cm. as the corresponding wave-length.] 

I propose, if you approve, to call ripples , waves of 
lengths less than this critical value, and generally to 
restrict the name waves to waves of lengths exceeding 
it. If this distinction is adopted, ripples will be undula 
tions such that the shorter the length from crest to 
crest, the greater the velocity of propagation ; while for 
waves the greater the length the greater the velocity of 


propagation. The motive force of ripples is chiefly cohesion ; 
that of waves chiefly gravity. In ripples of lengths less 
than half a centimetre the influence of gravity is scarcely 
sensible ; cohesion is nearly paramount. Thus the motive 
of ripples is the same as that of the trembling of a dew- 
drop and of the spherical tendency of a drop of rain or 
spherule of mist. In all waves of lengths exceeding five 
or six centimetres the effect of cohesion is practically 
insensible, and the moving force may be regarded as 
wholly gravity. 

Lord Kelvin s scattered papers on Waves have 
never been reprinted. If collected, along with those 
on Vortex Motion, they would form an appropriate 
fourth volume of his Mathematical and Physical 
Papers. In 1886 he gave, at the British Associa 
tion meeting at Birmingham, four papers on wave 
subjects : on Stationary Waves in Flowing Water ; 
on the Artificial Production of a Standing Bore ; 
on the Velocity of Advance of a Natural Bore ; 
and a graphic illustration of deep-sea waves. In 
the same year he discoursed at Edinburgh on waves 
produced by a ship advancing uniformly into smooth 
water, and on ring-waves. To the Royal Society, 
in 1887, he gave a paper on the Waves produced 
by a Single Impulse. On August 3, 1887, when 
the Institution of Mechanical Engineers met in 
Edinburgh, he delivered an evening lecture on 
Ship- Waves. This is reprinted in Vol. III. of 
his Popular Lectures. 

He began by defining waves, generally, as "a 
progression through matter of a state of motion." 
After further definitions he remarked that waves of 

xvin WAVE MOTION 749 

water have this great distinction from waves of 
light or waves of sound, that they are manifested 
at the surface or termination of the medium or 
substance whose motion constitutes the wave. 

It is with waves of water that we are concerned to 
night ; and of all the beautiful forms of water-waves, that 
of ship-waves is perhaps the most beautiful, if we can 
compare the beauty of such beautiful things. The subject 
of ship-waves is certainly one of the most interesting in 
mathematical science. It possesses a special and intense 
interest, partly from the difficulty of the problem, and 
partly from the peculiar complexity of the circumstances 
concerned in the configuration of waves. 

Before one can follow out the complicated pattern 
of waves which is seen in the wake of a ship travel 
ling through open water, it is necessary to study the 
simpler case of waves travelling along a canal. Of 
these a beautiful investigation was made in 1834 by 
Scott Russell, who found that, while short waves 
travel slower than long ones, there is a particular 
or critical speed for " long waves," that is, waves 
whose length from crest to crest is many times 
greater than the depth of the canal. For these the 
law holds good supposing water to be perfectly 
free from viscosity that their speed is equal to 
that which a body acquires in falling through a 
height equal to half the depth of the canal. Thus 
in a canal 8 feet deep the natural velocity of the 
" long wave "is 16 feet per second. Now if a boat 
is dragged along a canal at a speed slower than the 
critical velocity there is always seen a procession 
of waves behind it. In fact, if water were a perfect 


fluid, then a boat dragged along at any velocity 
less than the natural speed of the long wave in the 
canal would be followed by a train of waves of so 
much shorter length that their velocity of travelling 
is the same as the speed of the boat ; and the boat 
will seem to ride behind the crest of the first wave. 
These waves wash against the banks of the canal. 
To produce and maintain them consumes power. 
Much of the power required to drag a boat along a 
canal is wasted thus in wave-making. Moreover, 
water is not a perfect fluid : it possesses a certain 
amount of viscidity, though less than that of treacle 
or thick oil. The effect of this viscosity is to cause 
the cessation of the hindmost waves of the pro 
cession, which die out by fluid friction. The 
velocity of the front of a procession of waves is 
different, as Stokes and Osborne Reynolds have 
shown, from the velocity of progress of a wave 
itself. If the depth be greater than about three- 
quarters of a wave-length, the rate of progression 
of the rear of the procession of waves will be half 
the speed of the boat. Now comes a most wonder 
ful result : if the speed of the canal-boat be more 
rapid than the speed of the " long wave," it cannot 
leave behind it a procession of waves ; it travels 
along on the top of a sort of hillock or hump of 
water which travels along with the boat. As it 
makes no waves, the wave-making resistance is 
gone, and it is far easier therefore to draw the boat 
fast than to draw it slower with a whole procession 
of waves following. If a boat is drawn slowly it 



makes waves ; draw it faster, it makes more waves 
and requires more effort ; draw it still faster, so as 
to reach the critical velocity. Once that speed is 
reached, away goes the boat merrily, leaving no 
wave behind it. This was discovered accidentally 
early in the nineteenth century on the Glasgow and 
Ardrossan Canal, by a spirited horse which took 
fright and ran off, dragging the boat with it, and 
led to the establishment of a system of express 
" fly-boats " drawn by a pair of galloping horses. 
Of this singular circumstance Sir William Thomson 
found a theoretical confirmation in his mathematical 
investigations of 1886-87. Applying what is known 
of canal-waves to the movement of ship-waves in 
the open sea, Sir William Thomson then showed 
that the beautiful diverging pattern is comprised 
between two straight lines drawn from the bow of 
the ship backwards, with an angle of 38 56 between 
them, with a definite echelon of steep waves across 
the track following the ship. All this and more he 
described in the lecture at Edinburgh. He con 
cluded with a suggestion that since wave-resistance 
depends almost entirely on action at the surface of 
the water, it might be possible for swift ships to 
get high speeds of 18 or 20 knots by designing 
their hulls with a form swelled out below say with 
breadth of beam five feet more below the water- 
line than at the water-line instead of with vertical 

Even the veriest trifles about waves or wave- 
making claimed Sir William Thomson s attention. 


He wrote once to Lord Rayleigh this para 
graph : 

We saw a fine mode of generating a regular proces 
sion of periodic ring-waves in water. We were watching 
a set of ducks yesterday on our arrival here [Netherhall], 
and the beautiful echelons of waves which they made 
when swimming. They seemed pleased at being noticed, 
and one after another stopped swimming and called out 
to us in their own language ; each about twenty very- 
regular periods. By looking at the ring-waves we could 
count the number of quacks we had heard. 

In his last years Lord Kelvin communicated 
several mathematical papers to the Edinburgh 
Royal Society in continuation of these researches. 
They were on the Front and Rear of a Free 
Procession of Waves in Deep Water (1904); on 
Deep-Water Ship-Waves (1905); and Initiation 
of Deep- Sea Waves of Three Classes (1906). 



ARTIFICIAL though the division of time into decades 
may be, there are instances where it well fits the 
march of affairs. If in the development of the 
electrical , industry the sixties were notable for sub 
marine telegraphy, and the seventies for the siphon- 
recorder and the telephone, the eighties were no 
less so for the outburst of activity in electric lighting. 
So soon as sound engineering construction had been 
applied to the magneto-electric generator, and the 
mechanical production of electric currents had been 
thus assured, electric lighting was bound to pro 
gress. Already the arc lamp was in limited use. 
The year 1878 had seen the Avenue de 1 Opera in 
Paris lit with Jablochkoff s now historic "candles"; 
and a little later Swan and Edison had brought the 
carbon glow-lamp into precarious existence. The 
demand was springing up for improved generators, 
for better lamps, for switches and safety devices, 
and, above all, for measuring instruments. From 
this development it was impossible for Lord Kelvin 
to keep aloof. His advice and counsel were sought 
by capitalists who saw in electric-lighting schemes 



a possible development of commercial importance. 
With his engineering instincts he could not but 
busy himself with these things, and the years from 

1880 to 1893 are marked by a great devotion to the 
invention of patented devices. His compass and 
sounding machine were barely completed, and he 
was still patenting improvements in them at inter 
vals down to 1890. The long series of his patents 
for electric measuring instruments, gauges, and 
meters, begins in 1881, and continued till 1896. 
Electric lamps he touched only as regards improved 
means of suspension, in 1884. Dynamo-electric 
generators claimed his attention from 1881 to 1884; 
but he made no radical departure. A dynamo with 
a disk-like ironless armature, and another with an 
armature of copper bars like the bars of a squirrel- 
cage, which he designed, attained to no success. He 
also proposed rotating copper collectors to replace 
the spring brushes of the ordinary dynamo ; but 
they never came into commercial use. The zigzag 
winding for alternators, associated usually with the 
name of Ferranti, he invented independently in 

1 88 1 ; and the Ferranti machines were manu 
factured under agreement with him with a 
guarantee of a minimum royalty of ^500 per 
annum. His great ingenuity, command of 
mechanical devices, and wide experience in pre 
cise electrical measurement, combined to bring 
him success with his instruments for measuring 
electric currents and potentials. These instru 
ments, manufactured by the firm of James White 


and Co., in which he was now the chief part 
ner, were not, however, developed without im 
mense labour, and passed through innumerable 
changes before reaching commercial form. He 
thought in steel and brass, and must continually 
have the incipient instrument before him when 
working out the details ; alterations were then 
made and put to the test. The tests suggested 
some further change or improvement, and thus many 
visits must be made to the workshops, and many 
experimental trials in the laboratory, so that the 
development, if sure, was both slow and costly. 

The first instruments suitable for use in con 
nection with electric lighting were his graded 
potential galvanometer and his graded current 
galvanometer. The one was a portable volt-meter, 
the other a portable ampere-meter, both being 
developed from the tangent galvanometer modi 
fied for new service. They were followed by a 
magneto-static current-meter and by marine volt 
meters and ampere-meters, and by ampere-gauges 
for use on switchboards. Of the latter a whole 
series had to be devised to measure currents from 
^ ampere up to 6000 amperes. All these were 
electromagnetic instruments. 

Another series for measuring potentials was 
based on electrostatic principles, and may be 
regarded as being developed from the quadrant 
electrometer of 1860. By the multicellular con 
struction instruments were made, some of them 
reading as low as 40 volts, others as high as 1600 


volts. For higher voltages other types were used ; 
and electrostatic balances, based on the absolute 
attracting electrometer, were made to read up to 
50,000 or even 100,000 volts. In these instru 
ments nothing is more remarkable than the con 
fident way in which, defying the traditions of the 
ordinary instrument-maker, he insisted on intro 
ducing kinematic principles geometric slides, for 
example, to give the right number of degrees of 
constraint. The " hole-slot-plane " arrangement of 
support, in place of the old three-pointed levelling 
screws standing on a sole -plate, is due to Sir 
William Thomson. " His inventions," wrote Pro 
fessor FitzGerald, "are the direct outcome of the 
most advanced theory. He is a living example of 
the necessity for theory, in order to advance 
practice as much as possible." 

A third and later series of instruments is that 
comprising his standard electric balances, based on 
the electrodynamic principle of weighing the forces 
between movable and fixed portions of an electric 
circuit. Finding in all the earlier electromagnetic 
instruments inherent limitations as to range of use 
and as to accuracy within that range, Sir William 
fell back upon the fundamental discovery of Ampere, 
and set himself to devise apparatus that should 
require neither springs nor magnets, and in which 
gravity should be the controlling force. Further 
more, they could be rendered free from all per 
turbations due to the neighbourhood of any mag 
netic apparatus, or to local variations of terrestrial 



magnetism by astatic duplication of parts. Accord 
ingly, in each balance two ring-coils were set at 
the ends of a balance-arm, each such movable ring- 
coil being situated between an upper and a lower 
fixed coil. The tendency of the current to depress 
one end of the arm and raise the other could then 
be counterpoised by weights resting on the balance- 
arm, or moved along an attached steel - yard. 
Immense ingenuity was shown in the design of 
details, in particular in the device for shifting the 
weights along the graduated arm by a light silk 
cord running through the case of the instrument. 
Another notable device was the use of suspending 
ligaments, consisting of a vast number of very 
thin parallel wires, for supporting the trunnions of 
the balance-arm, instead of pivots or knife-edges. 
It was necessary to provide means of carrying into 
the movable ring-coils the strong electric currents 
to be measured, and this would have been quite 
impossible with pivots or knife-edges, or with any 
previously known means of flexible connection. 
The designing of recording meters for electric 
supply extended over a long period. In the 
earliest of these the integrator of his brother James 
was applied, but gave place eventually to simpler 

Work for pure science was never dropped during 
these years of devotion to practical inventions. In 
the spring of 1880, under the impulse of writing 
the Encyclopedia article on Heat, various researches 
on steam-pressure thermometry were undertaken, 


and their results communicated to the Royal Society 
of Edinburgh. He lectured in March on Mag 
netism, at Largs, and in May on the Compass, to 
the United Service Institution. Lady Thomson 
wrote in April to Professor George Darwin, that 
they proposed to spend June, July, and August in 
yachting, and added, " We are in great spirits over 
the elections ; I don t know if you are." The 
general election of that year had brought a sweeping 
victory for Mr. Gladstone. In the middle of May 
Sir William and Lady Thomson paid a visit to 
Charles Darwin at Down. No record has been 
preserved of the occasion ; but the two men had a 
good deal of talk, and parted with mutual respect 
and admiration, though their whole interests lay in 
different directions. 

A letter of Professor James Thomson to Pro 
fessor George Darwin, to which Sir William added 
the postscripts here printed in italics, tells of doings 
on the yacht, whither, after a visit to London to 
receive the Albert medal 1 of the Society of Arts, he 
had retreated to " get away from all animate and 
inanimate bores." 

Friday, i$th June 1880. 

MY DEAR MR. DARWIN I am along with my wife 
on a yachting cruise with my brother and Lady Thomson 
along the West Coast of Scotland, going northwards. 
We have to-day landed at Prof. Blackburn s place, Roshven 
on Loch Ailort, having passed Ardnamurchan Point 

1 The terms of this award were : " On account of signal service rendered 
to Arts, Manufactures and Commerce by his electrical researches, especially 
with reference to the transmission of telegraphic messages over ocean cables." 



yesterday afternoon and during the night in fog and calm, 
which made us have to He to during most of the night. 
My brother has his newest sounding machine and depth- 
gauge on trial for the first time in their latest forms of 
development by natural selection, and he was quite in 
earnest feeling his way along the bottom yesterday in the 
fog by taking soundings and comparing his results with 
soundings marked on the chart, in from jo to 105 fathoms. 

On arrival here I received your letter about ripple 
marks. My daughter had opened it for me in Glasgow, 
and she sent me a copy of one of the two passages in 
Lyell which you referred to. It is from Lyell s Elements 
(page 19), and as it tells a good deal of detailed informa 
tion and reasoning, I suppose it gives most of what you 
wanted to refer me to. She was not able to find anything 
about ripple marks in our edition of Lyell s Principles. 

I write at present chiefly to acknowledge receipt of 
your letter. I have thought often a good deal about the 
ripple mark, but have never yet seen how to clear the 
matter up. I think perhaps I may be able to offer some 
one or two suggestions tending towards true theory ; but 
I have not time just now. I would like if manageable to 
talk over the matter with my brother first, and perhaps I 
may write to you again before we sail from this place 
Loch Ailort. 

Mrs. Thomson and Lady Thomson and Sir William 
Thomson join me in kind regards, and I am, yours truly, 

George H. Darwin, Esq. 

[P.S.] My wife adds that it has been such beautiful 
quiet sailing all the cruise that it would have suited you 
perfectly, and she wishes you had been with us. W. T. 

A month later Lady Thomson wrote from Cowes, 
asking Darwin to join them on the yacht. " Sir 
William is supremely happy, and appreciating the 
life afloat more than ever." After another month 
Sir William wrote : 


SCILLY ISLES, Aug. 22/80. 

DEAR DARWIN You see how well the pen does. It 
has already written many letters and postcards, and has 
even superseded pencil occasionally in the green book 
with excellent effect. It should have thanked you before 
now, but that somewhat incessant cruising Cherbourg, 
Torquay, Penzance, Scilly has given it too much of a 
scramble for almost every postal opportunity since it came, 
to let it do so properly. 

Don t forget to tell me how much fresh grant for lunar 
gravity and terrestrial palpitations is to be applied for at 
Swansea. We sail from St. Mary s Roads here to-morrow 
forenoon, hoping to arrive there by Wednesday morning, 
if not sooner. We have had some very good sailing, and 
if you had been with us I am sure you would have enjoyed 
our anchorage here, after " standing off and on " all night 
waiting for daylight, and the visit to Tresco Abbey and 
its plants of all climates. . . . 

The " awkward infinity " threatens quite a revolution 
in vortex motion (in fact a revolution where nothing of 
the kind, nothing but the laminar rotational movement, 
was even suspected before), and has been very bewildering. 
Only to-day I have begun to see light through it, and a 
great deal that it has led to. I hope to be able to say 
something about it in Section A at Swansea. 

I am sorry you did not come with us to Cherbourg. 
The going and lying at anchor there, and coming thence 
to Torquay, would all have tested and fortified your sea 
going qualities. The sounding machine and depth-gauge 
worked most satisfactorily in as rough circumstances as 
they are likely to meet with practically in ordinary use 
at sea. 

Swansea was the scene of the British Association 
meeting in August 1880; and there Sir William 
read three papers on Vortex Motion, one on his 
Depth-gauge, one on the Sounding Machine, one 


on Contact Electricity, and one on the Critical 
Temperature of a Fluid. 

In October he was back in the Clyde adjusting com 
passes on the Czar s yacht Livadia, and teaching the 
use of the sounding machine to the Russian sailors. 

On December 18 he wrote to Dr. J. Hall 
Gladstone, urging him to stand as parliamentary 
candidate for Glasgow and Aberdeen Universities. 
" The tide has turned sufficiently to make a Liberal 
majority probable you ought to have a very good 
chance. ... I shall be very glad to look forward 
to your being our member if you will decide to 
stand, and I think you may do much good in many 
ways by being in the House." 

Christmas that year was spent as usual at 
Knowsley, followed by family parties at Druid s 
Cross and Mere Old Hall, Knutsford. 

The year 1881 was one of exceptional activity. 
The revision of " Thomson and Tait " for the new 
edition had long been on hand ; and the editing of 
the second part of Vol. I. had been entrusted to Pro 
fessor (now Sir) George Darwin. On January 17 
Lady Thomson wrote to Darwin for Sir William, 
" who is sitting on the sofa deep in a new depth- 
gauge, simpler than any you have seen," sending 
him a message about the effect of continents in 
setting up harmonics of the second order in tidal 

Fleeming Jenkin wrote to him about a new heat- 
engine, which promised great things, and received 
the following reply : 



I am much interested in all you tell me of your heat- 
engine. I think something of the kind, whether for solid 
fuel or gas (did you see the report of Siemens lecture here, 
according to which gas is to be the fuel ?) is to be the thing 
of the future, the steam-engine a thing of the past. I am 
to be in Edin. for the second R.S. meeting of this month 
(we shall be staying at the Crum Browns from the Sat. 
till the Tuesday) and I hope you will be able to show me 
your furnace and experiments then. I am afraid, however, 
that I could not join the proposed company. I am more 
than fully occupied with compass and sounding machine, 
etc., and I have spent so much money on them (including 
as a small item 3 compass patents for England and 
America, 2 sounding machines, etc. etc., and sounding 
machine patent for France, and Germany also) that I am 
not able to find 2000 for another undertaking, how 
ever promising, nor time and thoughts to give to an 
inventing company. I hope, however, that you will 
find all the assistance and support you want when you 
have so good a thing in hand, and such promising results 
to offer. 

On February 1 1 Sir William lectured on Light 
house Characteristics (see p. 727) at the Naval and 
Marine Exhibition at Glasgow. He was interesting 
himself deeply, too, in Mr. Anderson s Patent Law 
Reform Bill, then before the House of Commons, 
and wrote upon it in The Times of February 24. 
March i saw Sir William in London reading to the 
Civil Engineers the famous paper on his Tide-gauge, 
Tidal Harmonic Analyser and Tide Predicter de 
scribed on pp. 730-31 above. The reading and dis 
cussion of this paper lasted three evenings. On 
March 4 Sir William described to the United 
Service Institution his navigational sounding 
machine and depth-recorder, and in the evening of 



the same day discoursed at the Royal Institution 
on Elasticity (see p. 743). Two letters to Helmholtz, 
who was coming to London to deliver the Faraday 
lecture to the Chemical Society, relate Thomson s 
next movements : 

March 13, 1881. 

MY DEAR HELMHOLTZ For the last three months I 
have been always intending to write and thank you for 
having sent me such an excellent student as Mr. Witkowsky, 
but time has flown too fast, and now I write urgently to 
ask you to come and see us in Glasgow on the occasion 
of your visit to England at the beginning of April. I am 
coming up from Glasgow to London on purpose to hear 
you lecture on the 5th of April, and to meet you at the 
Chemical Society s dinner on the 6th. I would remain 
in London till Saturday the Qth, when both you and I 
having heard Tyndall s lecture on the Friday evening, 
would be ready to leave London. So I do hope you 
will come to Glasgow with me on the Saturday and give 
us as long a visit as you can. Lady Thomson (who is 
with me this time in London, but will not make the 
journey again in April) begs me to say that she looks 
forward with much pleasure to making your acquaintance 
in Glasgow, and joins me in hoping that you will say Yes 
to my request. 

On Monday (being a holiday) we might go to Largs, 
where we have built a country house, and for the rest of 
the week the laboratory will be at full work again. On 
Monday the 1 8th we might go to Edinburgh and see 
Tait, etc., and attend the meeting of the Royal Society 
there on the Monday evening. 

On Wednesday I return to Glasgow, having been here 
for a fortnight on account of four lectures which I have 
been giving. Let me have a line addressed to me here, 
and above all things let. it be Yes. Believe me, always 



DEAR HELMHOLTZ I am very glad to have the 
prospect of seeing you here on the I5th of April. I hope 
it will turn out that your Cambridge engagement will not 
prevent you from coming. I now write on the part of 
Lady Thomson and myself to say that we hope Mrs. 
Helmholtz will come with you, and that you will stay 
with us as long as you can. Perhaps Mrs. Helmholtz 
would stay here while you and I go to Edinburgh for the 
R.S. meeting on Monday the i8th, and return here on 

I am going to London on Thursday night, and to 
Portsmouth on Friday evening. I shall be glad to hear 
from you when we may expect to see you. If you write 
by return of post address me here ; if any day later this 
week address care of Capt. Fisher, R.N., Crescent Lodge, 
Southsea, Portsmouth. 

I am to stay with the Spottiswoodes in London, where 
I shall be on Monday the 4th of April. 

Excuse haste, and believe me, yours very truly, 


Two days later, Lady Thomson wrote to Darwin 
that Sir William had had a tide-gauge set up in 
the Clyde, only about fifteen minutes walk from 
the University a constant source of interest. " He 
is very deep in electric light too just now also 
telephone companies. . . . You would meet Prof. 
Helmholtz here about i5th or i6th if you come." 

Again, a note to Helmholtz : 

PORTSMOUTH, April 4 [1881]. 

DEAR HELMHOLTZ I go to London to-morrow 
morning to stay with the Spottiswoodes, 41 Grosvenor 
Place. I arrive there at 1 1 o clk., and will go on im 
mediately anywhere I can find you ; so please let me 
have a line which I may find on my arrival at Spottis- 
woode s to say where I must go to find you. You will 


no doubt be busy to-morrow in the prospect of your 
lecture for the evening, but I must just see you, if only 
to fix a time for Wednesday, when we can go anywhere 
and do anything together. Believe me, yours always 
affectionately, WILLIAM THOMSON. 

It was in the spring of 1881 that Sir William 
Thomson became interested in the Company which 
had been formed by Sir Joseph W. (then Mr.) Swan 
and his friends in Newcastle for the manufacture of 
the Swan glow-lamp. Though Sir William declined 
to take any official post as Director or Technical 
Adviser, he accepted the unofficial position of 
honorary consultant, and from time to time assisted 
the Company in that capacity. 

Returning on May 1 1 from London after a brief 
cruise in the Lalla Rookh, Sir William Thomson 
found a new scientific sensation. News had come to 
England of the production in Paris by Camille Faure 
of a secondary battery or accumulator for the storage 
of electric energy. The Times of May 16 contained 
a letter from Major Ricarde Seaver, announcing 
that he had brought over from Paris a box contain 
ing a million foot-pounds of stored energy, which 
he was taking to Glasgow to Sir William Thomson 
to be tested. Sir William, who apparently had 
never before appreciated the beautiful and patient 
researches of Gaston Plante, extending from 1869 
to 1878, on the formation of secondary cells of 
lead, and their use in electric storage, was 
immensely seized with the new invention, and 
fell upon it with more than his wonted energy. 


On May 17 he wrote from Netherhall to Dr. 
Gladstone : 

We are just setting out for a day or two s cruise in the 
Clyde, to test sounding machine and depth-gauges, but 
this address will find me. The " box of electricity " is 
being kept under continued tests and measurements by 
James Bottomley in my absence. It is splendidly power 
ful, but I have yet to find whether it does the whole 
amount of work specified by Mr. Reynier (and Mr. Faure), 
and how much actual work must be spent on it each 
time to renew its charge. 

He had, unfortunately, just then been seized with 
an illness, one of the recurring sequelae of the accident 
to his leg twenty years before, which obliged him 
to remain in bed for over three weeks. This did 
not in the least diminish his ardours. The whole 
laboratory staff was kept at work early and late 
experimenting, manufacturing new cells with red 
lead and sulphuric acid, charging and discharging 
the batteries, and reporting every detail at the 
bedside of the patient. A Swan lamp, fed from 
batteries made in the laboratory, and hung by a 
safety-pin to his bed-curtain, created great astonish 
ment in the many visitors who called on him. He 
wrote from the University to Jenkin on June 3 : 

I am about as well as possible, but the doctors said I 
should have to stay in bed for a fortnight at least. I 
shall be all right in a few days with absolutely no residual 
evil. I think very probably the fortnight will be shortened. 
Meantime I have plenty on hand in the way of proofs 
and outlying math 1 work. They are as hard at work as 
possible in the laboratory on the Faure storage cells, 
which are doing splendidly. It is going to be a most 


valuable practical affair as valuable as water cisterns to 
people whether they had or had not systems of water- 
pipes and water-supply. 

He had a long letter in The Times of June 9, 
which also had a long article on the subject. He 
stated that he had now subjected the battery to a 
variety of trials in his laboratory for three weeks, 
and that he was continuing the experiments at the 
request of the Societd Anonyme la Force et la 
Lumiere, which owned Faure s patents. He was 
interested in seeing in it " a realization of the most 
ardently and unceasingly felt scientific aspiration of 
his life an aspiration which he scarcely dared to 
expect or to see realized." The problem of storage 
was "one of the most interesting and important in the 
whole range of science." Already the battery in his 
laboratory had been found useful in surgery for 
cauterizing. The largest useful application awaiting 
the Faure battery was, however, to act as a cistern 
does to a water supply, as in the event of a stoppage 
or break-down of the machinery it would prevent 
failure of the light. The Faure accumulator, kept 
supplied from the engine by a supply main, will be 
always ready at any hour of the day or night to give 
whatever light is required. Precisely the same 
advantages in respect of force would be gained by 
the accumulator when the electric town supply is, 
as it surely will be before many years pass, regularly 
used for turning-lathes and other machinery in work 
shops and sewing-machines in private houses. All 
this and more his letter set forth. 


On June 17 Lady Thomson wrote to Darwin : 

Sir William sends to tell you that he has been 
absolutely forced off the air problem just when he was 
so exceedingly interested in it he hopes to go back to 
it again before long (but I don t know when !).... He 
has been so taken up with his " potted energy " that he 
has had no time for anything else. The laboratory is 
very hard at work making Faure accumulators and 
measuring their work. James Bottomley has gone to 
Paris to help them with their scientific work there. Sir 
William is tremendously interested in it. We are going 
to have electric light in the Lalla Rookh with its aid. I 
am sorry to say we are here. We had about a fortnight 
of yachting, and had just come up here again to prepare 
to go south, and have been delayed by Sir William 
getting laid up. It is nothing serious, but he has been 
three weeks in his bed ! Can you imagine his bearing it 
patiently ? but he does, and keeps everybody busy about 
him, and for himself the day is never half long enough. 
We shall be here at least ten days longer and we are 
due everywhere ! Paris London Portsmouth, and the 
poor Lalla Rookh is lying idle at Largs. 

June 21. ... Sir William is still a prisoner. ... I 
am general secretary just now, so you may imagine I am 
pretty busy. Rennie [Sir William s amanuensis at that 
date] is working in the laboratory. They are so short- 
handed there just now. 



I dare say you saw The Times City letter and Major 
Seaver s letter in reply re Force et Lumiere. I hope 
that the proprietors of Faure s patents, the " Societe" la 
Force et la Lumiere," are going to buckle to the real 
work of manufacturing and supplying accumulators, and 
that no formations of monster companies will continue to 
form any part of their plans. They have a splendid 



thing in hand, and I am very anxious to see it worked 
out well. Yours, W. T. 


DEAR JENKIN Have you any good man to spare 
who knows something of electricity and engineering, and 
French, supposing I want to send a man to Paris to 
take charge of testing and inspecting in the manufacture 
of Faure accumulators ? 

J. T. Bottomley is there at present, and I intend to go 
in about a fortnight, but it is possible we shall have to 
leave some one in charge. 

White has been appointed, under my direction, sole 
agent for the manufacture and sale of Faure accumulators 
in the United Kingdom. Yours. W. T. 

By July 9 Sir William was well enough to be in 
London, on his way to join his yacht at Portsmouth, 
where he was busy with the Inflexible, settling her 
compasses, and seeing to her experimental equip 
ment with " potted energy " in the shape of storage 
batteries for electric lighting. He was also busy 
arranging with the Jay Gould cables for the use of 
mirror galvanometer and siphon recorder. Then 
back again in London, he stayed for six weeks 
at the Grand Hotel, busying himself personally 
to arrange with Mr. Fender, Dr. C. W. Siemens, 
Mr. E. P. Bouverie, Mr. I. Lowthian Bell, Sir 
John Lubbock, Mr. C. Seymour Grenfell, and 
Captain Douglas Galton, to form a company to 
exploit the Faure battery. The agent of the 
French patentees, M. Philippart, had a marvellous 
genius for drafting prospectuses, and evolved 
scheme after scheme. All schemes had the feature 
of showing immense future prospects of profit to 


the investors, and all were arranged to bring to the 
vendors a sum varying from a quarter to half a 
million pounds. He induced Sir William, whose 
labours up to this point had been purely voluntary, 
to enter into an agreement to act as technical 
adviser, receiving in return 10 per cent of the 
capital. Sir William insisted that the fact and 
extent of his interest should be published. To this 
course M. Philippart objected. The owners of the 
Faure Patents proposed the enormous capital of 
^400,000, of which they were to receive 120,000 
in cash and half the shares. The negotiations lasted 
through August, as one by one withdrew from taking 
part in so formidable a venture ; but it was not till 
some weeks later that Sir William was brought to 
realize the very unsatisfactory position ; and he too 
withdrew a heavy loser by the affair from all asso 
ciation with the venture, though he wished the inven 
tion success. He was keen to light his own house 
at the University by Swan lamps and Faure cells. 

The year 1881 being the Jubilee of the British 
Association, its meeting in York the city of its 
foundation was one of unusual brilliance. Sir 
John Lubbock (now Lord Avebury) presided ; 
and Sir William Thomson was chosen once more 
as president of the Mathematical and Physical 
Section. He took as the topic of his Address the 
Sources of Energy in Nature available to Man for 
the Production of Mechanical Effect. Beginning 
by remarking how the science of Energy had prac 
tically arisen during the fifty years of the existence 



of the Association, he reverted to his earlier paper 
of 1852 (see p. 289), in which he had enumerated 
the natural sources of available power food for 
animals, natural heat, potential energy of elevated 
masses, natural movements of air and water, natural 
combustibles, and artificial combustibles. Heat 
radiated from the sun was undoubtedly the chief 
source, and a second possible one was the tides due 
to the earth s rotation. Of the natural sources, 
tides, food, fuel, wind, and rain, only one, the tides, 
was not derived from sun-heat. Tide-mills existed 
indeed ; but the vast costliness of dock construction 
was prohibitory of almost every scheme for utilizing 
tidal energy. Parenthetically he praised the metric 
system, "to which we are irresistibly drawn, not 
withstanding a dense barrier of insular prejudice 
most detrimental to the islanders." As the sub 
terranean coal-stores of the world were becoming 
exhausted, surely and not slowly, the price of coal 
was upward-bound, and it was not chimerical to 
think that in some form windmills or wind-motors 
would again assume ascendency. Even now they 
might be used for lighting. Now that we had 
dynamos and Faure cells for storage, the chief 
want was cheap windmills. Rain -power was not 
economical except as the natural drainage of hill 
country. For anything of great work by rain- 
power, the water-wheels must be in the place where 
the water - supply with natural water was found. 
" Such places are generally far from great towns, 
and the time is not yet come when great towns 


grow by natural selection beside waterfalls, for 
power." But the splendid suggestion of Siemens, 1 
that the power of Niagara might be utilized 
by transmitting it electrically to great distances, 
had given a fresh departure. From the time of 
Joule s experimental electro - magnetic engines, 
and by the theory of the electro -magnetic trans 
mission of energy, it had been known for thirty 
years that potential energy could be transmitted by 
means of an electric current through a wire, with 
unlimitedly perfect economy. Adopting Siemens s 
shortened form of the word, he declared in con 
clusion that " dynamos " give now a ready means 
of realizing economically on a large scale many 
practical applications of Joule s thermodynamics of 
electro-magnetism ; and, in particular, they make it 
possible to transmit electro-magnetically the work 
of waterfalls through long insulated conducting 
wires, and use it at distances of fifties or hundreds 
of miles from the source, with excellent economy. 

One passage of the address, not included in the 
reprint in Vol. II. of the Popular Lectures, is worth 
preserving : 

High potential, as Siemens, I believe, first pointed out, 
is the essential for good dynamical economy in the electric 
transmission of power. But what are we to do with 80,000 
volts when we have them at the civilized end of the wire ? 
Imagine a domestic servant going to dust an electric lamp 
with 80,000 volts on one of its metals ! Nothing above 
200 volts ought on any account ever to be admitted 
into a house or ship or other place where safeguards against 

1 Presidential Address of Sir William Siemens to the Iron and Steel Inst. 


accident cannot be made absolutely and for ever trust 
worthy against all possibility of accident. In an electric 
workshop 80,000 volts is no more dangerous than a 
circular saw. Till I learned Faure s invention I could 
but think of step-down dynamos. 

In the section meetings Sir William followed up 
the outlines of his address by reading papers on 
Some Uses of Faure s Accumulator in Electric 
Lighting; on the Photometry and the Illuminating 
Power of Electric Lamps ; on the Proper Propor 
tions to be given to the Resistances in the Different 
Parts of Dynamos ; and on the Economy of Metal 
in Conductors of Electricity. The last two were 
of importance. In the one he gave rules for the 
good design of shunt-wound dynamos ; in the other 
he enunciated the now famous law, that for economy 
in long-distance transmission of power at a given 
voltage the best economy is obtained when the 
conductor is of such a thickness that the interest on 
the capital expenditure on the copper is equal to 
the annual cost of the energy lost in transmission 
through the conductor. Though there is modifi 
cation needed for cases in which the cost of the line 
(for example, in extra-high voltage transmissions) 
other than the mere weight of copper is not pro 
portional to the mileage, " Kelvin s law" is still the 
foundation of practice. He also read a paper on an 
electro-ergometer, only to find that his proposal was 
the same as the wattmeter, shown to the section by 
Ayrton and Perry the same day. 

At this meeting there was a very keen discus 
sion on the report of the Committee on Electrical 


Standards, which had been reappointed on the 
motion of Prof. Ayrton the previous year. An 
International Congress the first of its kind was 
to be held at Paris in the middle of September, at 
the Electrical Exhibition, and it was keenly desired 
that other nations might agree to the system of 
units and standards which the British Association 
Committees had evolved, chiefly under Thomson s 
inspiration, since 1862. Joule had shown the 
original B.A. ohm (p. 419) to be slightly smaller 
than its intended theoretical value in the absolute 
centimetre-gramme-second system ; and new deter 
minations of the absolute values of resistances, 
currents, etc., had been made in different countries 
by Rayleigh, Mascart, Rowland, Roiti, H. F. Weber, 
and others. There was also a serious proposal to 
substitute for the practical units of current and 
voltage other units ten times as great, so as to make 
them agree with the " absolute " units. The Com 
mittee at York was divided on this point, and the 
proposal to keep the unit of current (then called the 
weber) at one-tenth of the absolute unit was carried 
by a bare majority, Sir William Thomson urging 
that the smaller value was more convenient, being 
about of the magnitude needed for one Swan lamp. 
"Alas! no West Highlands this year for us," 
wrote Sir William to Jenkin on September 9. 
" We are off to Spottiswoode s, Coombe Bank, this 
moment, and thence to Paris, Monday ; Netherhall 
a fortnight hence, hurrah ! " 

At the Paris Congress Sir William was a notable 


figure amongst the leaders of the electrical world. 
M. Cochery, Minister of Posts and Telegraphs, 
presided. The foreign vice-presidents were Sir 
William Thomson, Signor Govi, and Prof. Helm- 
holtz. Helmholtz, Werner Siemens, and Du Bois 
Reymond represented Germany, and there was a 
strong feeling in favour of abandoning the British 
Association s unit of resistance, the ohm, in favour 
of Siemens s unit, the column of mercury one metre 
long. The debate grew warm. One who was 
present has narrated the unforgettable scene of 
comedy of Thomson and Helmholtz disputing hotly 
in French, which each pronounced more suo, to the 
edification of the representatives of other nation 
alities. A severe disruption was averted by a 
timely adjournment, during which, by the efforts of 
M. Mascart and Mr. (now Lord Justice) Moulton, 
a compromise was arranged to accept the B.A. 
ohm, but to represent it concretely by a column 
of mercury of appropriate length, the precise 
value of which was to be fixed at an adjourned 
conference the next year, after further researches. 
The names of the electrical units, ohm, volt, 
farad, and coulomb were agreed to ; but that of 
the weber was changed to ampere, in honour of 
the great French savant. Sir William was the 
life and soul of the whole business of the Congress. 
While staying in Paris Sir William gave to the 
Academic des Sciences a paper on the Thermo- 
dynamic Acceleration of the Rotation of the Earth, 
which he had recently discovered. 


In October he learned that he had been awarded 
the Diplome d honneur at the Exhibition for his 
fine show of compasses, galvanometers, and other 
instruments and inventions. 

The important part which Sir George Darwin 
took in the revision of the Treatise occasioned much 
correspondence and is illustrated by the following 

note : 

DEAR DARWIN In the italics of 569 I think c. of i., 
though never heard of by either Pappus or Guldinus, 
ought, as you say, to be put in place of c. of g. But in 
572 it is really the approximate theorem of c. of g. that is 
used, and gravity that is the occasion for using it. There 
fore leave c. of g. in 572 and all similar cases. Yours, 

W. T. 

[/*..] I enclose another sheet for your imprimatur ; 
also a piece of slip of the preceding sheet. 

Sending more proofs on November 16, he 
wrote : 

I am tremendously obliged to you for what you are 
doing. . . . The truth is your help has been a great 
spurt to me. 

Within three days he was back in Glasgow 
arranging to light his residence and the University 
laboratory by Swan lamps, a Clerk 1 gas-engine, and 
Faure cells. 

On October 17 Lady Thomson wrote to Darwin 
that Sir William had gone off to the Inflexible at 

1 Sir William took part in a discussion on the theory of the gas-engine, 
after a paper by Mr. Dugald Clerk, at the Institution of Civil Engineers, 
April 4, 1882. 



last for a trip about the south coast, to end at 
Plymouth on the 27th, when he would go to 
Cambridge : 

Before he left on Saturday he bade me write to you 
to thank you very much, and to tell you what valuable 
assistance you have given in T and T ; he says in future 
it will have to be T and D, not T and T . . . . 

Nov. 4. Sir William says I am to tell you that he 
felt much humiliated by the number of blunders which 
you caught out. . . . He gave his first lecture on Wed y 
morning, and is already in full swing of his winter s work. 

The same day he wrote to Jenkin : 

You must have engine and dynamo to work the 
Swans, which, as you say, are lovely. The true domestic 
use of the Faure is for continuing a small amount of 
lighting after the main demand ceases when the engine is 
(thanks to it) to be let stop. . . . Excuse haste and 
shakiness of hand standing on my legs before I run 
out to my class. 

On December 8th Lady Thomson sent Darwin 
word that they had had a very pleasant visit from 
Mr. and Mrs. Hopkinson. " Sir William and he did 
nothing but talk electric light and dynamos ! " Sir 
William s house was then being wired for electric 
lamps. He added the following postscript to the 
letter : 

Thanks for the Adams [an estimate of geologic 
time], which will do splendidly for T & T . I am glad 
it is not a recantation. Why don t you want the earth 
consolidated as it is ? It is the probable history of the 
earth s emergence into the consistentior status : not com 
plete in every detail, but about as correct on the whole as 
any ordinary history of England. 



On December 26th Sir William wrote again 
from Knowsley : 

I have been engrossed with finishing one patent, and 
making the provisional of another, for two or three weeks, 
but I have brought all of both T & T and my reprint 
with me, so I hope to get something done in the holidays. 
Shall I send you sheets for your final imprimatur after I 
have done all I can on them, or would you rather wait 
till after the Tripos ? 

The following extract from a later letter on the 
rigidity of the globe has an interest of its own : 

Dec. 28, 1 88 1. 

. . . That a change from ellipticity of -^^ to ^-^ 
could take place in a body as rigid as the earth is as 
a whole, without leaving gigantic traces, I have always 
thought to be so very excessively improbable, that I have 
never doubted the validity of the assumption that the 
earth has not experienced it since consolidation, nor of 
any conclusion founded on this assumption. 

The durability of Africa and America have (sic) always 
to my mind been irrefragable proof of the permanent 
rigidity of the earth under stresses comparable with those 
due to angular velocity, giving comparable elevations and 
depressions of a complex level surface relatively to a 
surface through the same solid particles. It seems to 
me exceedingly improbable that the angular velocity can 
have changed by much more than -^ of its own amount 
since consolidation, because 1000 or 2000 or 3000 feet 
of elevation of equatoreal solid relatively to a level surface 
would not redress itself by the earth s yielding to over 
severe stress ; and even considering volcanoes, or whatever 
may be the cause of the greatest elevations and depressions 
that have taken place in geologic history, I do not think 
a 2000 ft. or 3000 ft. elevation of equatoreal land, by 
failing centrifugal force, could be lost among the other 
disturbances. I think it just possible that 1000 feet 



might be overlooked by us among the great changes that 
have taken place, and therefore I don t think Adams 
datum absolutely inconsistent with io 6 centuries of geo 
logical time. But if Adams datum is correct it would 
give some weight in the balance for arguing something 
less than that. I should think from 20 to 50 million 
years, all things considered, the most probable. Under 
ground heat, I suppose (not to speak of biology), makes 
20 x io 6 more probable than 5 x io 6 or than io. There 
are many reasons that make anything more than I oo x I o 6 
improbable, so far as I can see. 

Consulting Dr. Gladstone about the chemistry 
of accumulators, he wrote : 

22nd Dec. 81. 

DEAR GLADSTONE James Bottomley showed me 
your letter, and we are much interested in it, as well as 
in what you wrote to me about the Plante" and Faure 
batteries. My great difficulty all along has been to under 
stand how it is that the electrolytic action of the peroxide 
in contact with the lead plate upon which it is placed 
does not go on oxidizing the plate. I cannot see the 
conducting connection between it and the plate in contact 
with it, so as to allow the complete electrolytic surface of 
the coating to be in regular action, and yet not to cause 
oxidation of the lead plate in contact with it. I am also 
much puzzled about the function of the sulphuric acid. 
It is not simply to render the liquid a conductor. I have 
tried a Faure element without sulphuric acid, but hitherto 
with only negative results. It has hitherto been a com 
plete failure in respect to capacity ; and yet I believe I 
have sent enough of quantity through it, to produce a large 
action on the minium. However, the trials are incomplete, 
and I may get better results yet. 

I want to know why it is that the sulphuric acid does 
not form sulphate of lead, with the protoxide found in 
the battery. Is it that there is besides the peroxide, 
another oxide which is not attacked by sulphuric acid ? 


The liquid in my cells is sometimes quite destitute of acid, 
and is then replenished with dilute acid in the proportion 
of ten volumes of water to one of acid. 

The loss of the acid sometimes takes place several 
times in the process of forming a cell. The cells in which 
it goes on much are found to be bad ones, but I have 
not been able to find the cause of the badness. The 
presence of sulphate of lead on the peroxide, as I find 
it sometimes coating the peroxide over in places like 
disease spots, is certainly an evil ; not, I believe, merely 
by obstruction, but by somehow tending to let the cell 
discharge itself. Cells sometimes go bad, and on being 
recharged for a long time, become again as good as they 
were. The whole thing is in immense need of investiga 
tion, but the investigation is excessively difficult. 

I think it is going to be of great practical value not 
withstanding all these difficulties. I am on the point of 
beginning to light my laboratory, lecture-room, and house 
with Swan and Edison lamps. As an auxiliary for night 
lights and dark winter mornings, I shall have about 130 
cells (round) of the Faure battery, on the original pattern, 
which I made here last June and July. Many of them 
are bad, but on the whole I expect they will give the 
result I require, although not with perfect economy. I 
have got my house completely wired from attic to cellar, 
and I mean to have no gas and no candles. The gas- 
engine I am going to use will be in my laboratory, and 
I hope to find it running on my return from England, 
where we are to spend the holidays in Liverpool and its 
neighbourhood. . . . 

All through the year 1882 the revision of T & T 
occupied Sir William s time, and he wrote every 
few days to Darwin. On January i he sent word 
that he had " shortened the first day of the year 
considerably by a great despatch of Mathematical 
and Physical papers " to the printers ; and he was 


much bothered by 830 of T & T . The next 
day another note adds : " I am on my way to 
Glasgow for an odious affair in the Phil. Soc. 
to-night about gas-meters (awards/)." Many of 
these letters tell of other matters beside printers 
proofs. Sir William s house was the first in Scot 
land to be fitted with electric lights. He himself 
devised many details switches, fuses, suspensions, 
and such like. 

Feb. 15. I have been overwhelmed with electric 
lighting. It is going to be a great success in the house. 
It is already a great pleasure, but wants much much to 
complete it for practical convenience. 

In May, after the College session was over, 
there was a fresh outburst of correspondence on 
the parts of the book relating to tides and other 
matters. At last, on June n, he found himself on 
the Lalla Rookh in Lamlash Bay ; but, alas ! he had 
left the proofs behind at Netherhall. 

It is most unfortunate. Though we sailed much of 
yesterday, which is all-absorbing (the chief merit of 
sailing) ; but this is Sunday and wet all after church 
time, an opportunity sadly lost. I did look at proofs in 
the Pullman on Thursday night, but not by electric light, 
so detected no errors. 

June 15 (addr. Yacht, Lalla Rookh, Largs). I shall 
be here again next Thursday as eras ingens iter abemus 
aequor ; i.e. the gravity and kinetic equipotential on a line 
from Gareloch to Largs. 

A very characteristic letter to Darwin is the 
following : 




June 21/82. 

DEAR DARWIN P. 302 and the Tables of my 1876 
report are " utterly right " in respect to the epochs of the 
fortnightly and lunar semi-diurnal tides ; and your " f v " 
could but be met by an unqualified not guilty. . . . 

I must have been wrong in one of my marginal " oh 
no s " on one of your returned MSS. And I suppose the 
" ? " after " hinc " is to be answered in the negative. 

But why did you go on attacking 302, and Laplace 
and Hopkins? Their astres fictifs and mean suns and 
mean moons are a most valuable contribution to means 
of expression (alas ! an unintended pun) in physical and 
descriptive astronomy. It is the combination of aphasia, 
with heedlessness as to logical clearness and accuracy when 
aphasia is overcome that makes the whole difficulty in the 
ordinary dealings of astronomical writers with such ques 
tions as this that we have had in hand, which by aid of 
Laplace and Hopkins properly used (and not abused), as 
I have abused them to some degree, by not saying equa- 
toreal mean moon when I meant it, and orbital mean 
moon when I meant it, and ecliptic mean sun s longitude 
instead of even in a " and for a moment adopting 
" sun s mean longitude." . . . 

I don t know when this will be posted, as we are 
now (5.15) becalmed, rather far up Loch Long. I in 
tended to be up in Glasgow and have a trial of my 
potential regulator to-night ; but I am resigned. My 
dynamo at all events will not suffer, as this (LL.R. I 
mean) is the only place for scheming such things. Yours, 


[P.S.] Excuse the disjointed and untidy character of 
the above, as it was only possible to write during showers, 
so beautiful are the masses all round above the great 
equipotential ; till the weather became too fine and I put 
the stylograph in requisition on deck. 

Early in July the yacht started for a West 



Highland cruise, and on July 9 Sir William wrote 
from Crinan Bay : 

. . . You must give a paper to the B.A. Southampton 
on Fortnightly Tides and the Rigidity of the Earth. It 
is the fruit for which the B.A. Tidal Committee of 
1869-76 was sown, as you may judge from T & T 


My burning question for the last sheet but one of 
reprint has cost me a good deal more time and work 
(time chiefly spent in trying to read with complete in 
telligence 700-732 of Electrostatics and Magnetism} 
than I reckoned. I see my way pretty thoroughly now, 
I think, and I do hope to get it off, and the last of the 
vol. imprimatured, almost instantly. I have done a good 
deal, however, on the T & T proofs, and am only waiting 
to get a sentence or two written for 830, and possibly 
an addition from the Rede lecture for 1866 (Phil. Mag. 
1866, ist half-year) decided on. 

P. 5. The necessity for a depth-gauge not founded 
on the spring of air becomes more and more urgent, and 
has taken a good deal of my time from T & T and the 
reprint. It slumbers till I get to sea, and then comes 
on with renewed intensity. It has done so at all events 
these four years, every time. 

July 19 found the yacht at Roshven, and thence 
Sir William sent four pages about his reprint; next 
day four more about slope of potential ; the same 
evening eight more, highly mathematical ; and on 2 1 st 
from the Sound of Sleat another missive, a leaf 
(torn from his green-book) of mathematics, which he 
describes as " a very pleasing little nugget dug out 
of old 1847-8 neglected diggings since we left 
Roshven this morning." But all was not plain 
sailing, for the next letter tells of dire disaster. 



July 25/82. 

DEAR DARWIN We had a beautiful sail out of Isle 
Ornsay and through the Kyles of Skye and Loch Alsh 
on Saturday morning, and I unfortunately neglected, in 
consequence, to finish writing out the piece of theory of 
the day before. It would have been quite satisfactory and 
sufficient as to the elastic yielding of rock to weight of 
water, and would have kept me quite busy enough to keep 
me from a practical experiment which I made about 20 
minutes after high water on its yielding (proving it to be 
very small) to a much greater weight of wood and iron 
than the load of air or water that you have been thinking 
of. The result was that by the time of low water (5 P.M.) 
the wood had yielded very visibly and the rock not 
perceptibly. We left it there, on Scalpa, about 10 miles 
from this, and were brought here in a friendly steam yacht 
of 650 tons (Mr. Stewart s Amy) that chanced to pass 
by when the result of the experiment was becoming 
apparent. We were taken back next day, and Mr. Stewart 
set his crew to help mine and we baled and pumped the 
Lalla Rookh dry, and caulked the deck seams with tow 
and tallow, it having become apparent that it was through 
them that she had rilled after the two previous low waters, 
and we had to jetison her by taking about ten tons of 
matter out of her. She yielded half an hour after midnight 
to a third determined pull, which Mr. Stewart with splendid 
resolution and courage gave her, and came off. The elastic 
limits had been largely exceeded, and there is a large 
contortion of the strata, giving a mountainous and pictur 
esque character to deck and starboard side after the 
removal of the stress ; but she makes even less water than 
she did before (which was very little, quite as little as it 
ought to be), and she left this evening in tow of a tug I 
telegraphed to Greenock for yesterday morning. She will 
be made as good as ever very soon, in a week or two I 
hope, but not in time to come round with us to South 
ampton. So I am sorry to say our cruising, which was 
an unalloyed pleasure till the last instant of it when we 


were looking at a seal with our glasses, is over for the 
season ; and we cannot ask you to come and settle the 
earth s rigidity on board the Lalla Rookh (it having been 
temporarily settled the other way so far as she is con 
cerned). But we shall carry the war into the enemy s 
country and have our revenge with you on terra miscalled 
firma in some of the committee rooms at Southampton. 

The theory has, however, been developing itself (though 
not on paper) very prettily. Let me know if what I 
posted at Ornsay was sufficient, or at all events intelligible 
as far as it went. I was going to put into proper shape 
the reduction to calculable results which with m oo would 
have put into workmanlike shape the clumsy thing of 
Roshven. This part of the affair is simply done by 
taking in your crushing as unit of force the mutual 
attraction between two grammes of matter concentrated 
at two points i centimetre asunder (which for copper 
makes n = 450 x io 6 " grammes weight " per square centi 
metre). I had got on, before or after the seal, I forget 
which, to find the interpretation and an interesting physical 
illustration of the correction to annul surface tangential 
force which I had introduced in the Isle Ornsay despatch. 
Here it is. [Here follow fourteen octavo pages of mathe 
matics and diagrams, ending up] . . . 90, if the material 
does not break, as was the case of the L.R., where no 
doubt there was perfect tangency at bounding line of inter 
face between coppers and rock. Nothing more. Yours, 

W. T. 

Other letters followed very quickly. 

July 30, NETHERHALL. We are much grieved to 
hear of the death of Frank Balfour. It is indeed a sad 
loss to the world, which can ill spare such men. We 
feel very much for you and quite understand Cambridge 
being different to you without him. ... In haste to 
catch post, or rather to be not late for church, as letters 
must be posted before. . . . 

Aug. i, NETHERHALL. I must settle down now 


thoroughly to 830 and subsequent sheets of T & T r to 
the end. . . . You asked me why I chose so moderate a 
slab of water in T & T 8 818. Answ. because it is 

something we know about. Not very unlike, for example, 
the actual effect of the water in the English Channel on a 
plummet at St. Alban s Head. 

I have always admired Cavendish s experiment as 
perfectly free from error due to yielding of the foundation. 
His two attracting masses are supported on a pivot mid 
way between, so that the pressure on the ground never is 
changed during the experiment. 

Aug. 2, NETHERHALL. I am returning Title-page, 
Preface, and Contents of Math, and Phys. Papers^ Vol. L, 
for press by this post. . . . Reprint of Electrostatics and 
Magnetism is commenced, and Vol. II. of Papers is to 
begin as soon as T & T let me. 


(Address NETHERHALL), 

Aug. 14/82. 

DEAR DARWIN Till the moment of leaving Nether- 
hall on Saturday I was so driven, with a multitude of 
unavoidables, that I could not write a word on any of 
the points you have been writing to me about. On 
Friday I got the very last scrap of Vol. I. of Collected 
Papers out of my hands for press, so that is out of the 
way, and I have got fairly on to things for finishing 
the T & T vol., particularly the infinite homogeneous 
solid bounded by a plane (I wish you would give a non- 
self-contradictory designation for this). It comes out 
enchantingly, I mean the complete problem of any 
arbitrarily given distribution of surface force (3 com 
ponents, one normal and two tangential, for every point). 
I have been at it all my spare time since I came here, 
and may possibly get it written out for press to-morrow. 
... I shall look carefully to whether anything should be 
put into T & T 7 as to the effect of the weight of the 
water on the elastic yielding. . . . The plane-bounded 
infinite solid is too captivating to let me touch anything 
else till I get it off the stocks. Yours, W. T. 



Southampton was the place of meeting of the 
British Association in August 1882, under the 
Presidency of Dr. (later Sir) William Siemens. 
His brother Dr. Werner Siemens was a notable 
guest ; also the veteran Professor Clausius. Thom 
son read several papers ; on some new absolute 
galvanometers ; on the transmission of force though 
an elastic solid ; and on magnetic susceptibility. 
He also gave an evening discourse on the Tides 
(see p. 729). 

A distinguished geologist present has pre 
served the following account l of this event : 

. . . Sir William Thomson s lecture on the Tides, 
which was given to a large audience, was good for all 
who understood it. But Thomson himself was splendid ; 
he danced about the platform in all directions, with a 
huge pointer in his hand ; he shook in every fibre with 
delightful excitement, and the audience were as delighted 
as he. 

The adjourned Paris Conference on electric units 
was to be in October. On September 30 Sir 
William, then at Netherhall, wrote to Lord Ray- 
leigh asking if the date was to be the i6th, as there 
appeared to be some misunderstanding. 

Dr. C. W. Siemens, who is with us just now, tells me 
that you cannot be in Paris on the i6th, but I hope this 
is not the case. We could get on but very badly without 
you, and in fact I suppose your ohm must be declared 
the one true ohm for our generation. 

To Darwin he wrote on October i2th : 

I am going to-morrow to Newcastle to see Swan s light 

1 A Memoir of William PengeZly, p. 264. 


factory, and thence to Bolton s copper mills, Cheadle, on 
my way to London. 

Thence he wrote to Lord Rayleigh : 

LONDON, W.C., Oct. 13/82. 

DEAR LORD RAYLEIGH I have at last received a 
positive official notification that the i6th is fixed for the 
Units Committee, and I am going accordingly to Paris on 
that date. I don t leave London till Monday forenoon, 
so if you have anything more to send by me I shall be 
able to receive it by post. Dr. Siemens had left us when 
your letter (which crossed mine to you) and paper for 
him came, but I am to see him this evening and I shall 
give it to him. I shall bring the other copies with me and 
more for the members of the Congress if you will send 

But will you not come to Paris after all, taking leave 
of absence from Cambridge for the necessary time ? If 
you would come on Monday and remain a few days it 
would tend much to ease the way of the Congress to the 
settlement of the ohm, not to speak of other questions. 
Let me have a line here, unless you will cross over along 
with us by the tidal train for which we leave Charing 
Cross at 1 1 on Monday forenoon. Yours very truly, 


From Paris he wrote to Dr. Hopkinson about 

the muddle : 

Oct. 17/82. 

DEAR HOPKINSON On the 20th of September Lord 
Granville answered the French authorities that the names 
of proposed English delegates, and the fixture of the 1 6th 
as the commencement of the meeting, had been com 
municated to the Science and Art Department. So the 
fault seems to have been in South Kensington. I hope 
your telegram will bring it home to them, and, still more, 
that you will yourself be here to-morrow. 


Our Government seems to have determined to do as 
little as possible, and I think you did quite right in 
respect to the telegram you received yesterday morning. 

I think I must write a complaint, because I find 
myself put down as a delegate from England in an 
official list without having received any intimation that I 
had been appointed ; and I only hear of it here through 
the French. I shall not write, however, till I hear from or 
see you and learn the effect of your telegram of yesterday. 
I hope you will be here to-morrow, as the practical thing 
to be done is really important. A commission of I 5 on 
the measurement of the ohm, appointed to-day, meets to 
morrow. You of course will be on it. Yours very truly, 


[P.S.] Helmholtz, Wiedemann, Kohlrausch, Lorenz, 
Werner Siemens are all here, and all except Wiedemann 
and Kohlrausch in this Hotel. 

The next letter to Lord Rayleigh tells of the 
doings of the conference : 

Oct. 19/82. 

DEAR LORD RAYLEIGH We are all very sorry that 
you have been unable to be at the Conference, and I am 
charged to express " des vifs regrets " that you had been 
prevented by illness. 

The sous commission on the fixation of the ohm 
has held its last meeting to-day, and it is strongly im 
pressed with the conviction that your number -9865 x io 9 
is within Y^^S f ^ e true va -l ue of the B.A. unit (Would 
you not rather, however, take as the most probable -9867, 
being the mean of your result by the old B.A. method, 
and your two by Lorenz s method, -9869 and -9867 ?) I 
communicated this statement to them, from your letter, and 
also the statement that probably the comparison between 
the B.A. and the Siemens mercury unit, made independ 
ently, is trustworthy to ^^. I also communicated your 
printed slip, giving the results of your and Mrs. Sidgwick s 


comparison of the 4 tubes with the B.A. unit. This 
will all appear in the report of the meetings. I believe 
they would have decided on ( > 9867)~ 1 of the B.A. unit 
(or corresponding numeric of the S. U.) for the ohm, but 
that Friedrich Weber was there defending some carefully 
made experiments of his own, which gave him -9550 x 10 
for the Siemens unit, instead of -9413, as you and Mrs. 
Sidgwick make it. It seems after all probable that it was 
the particular one or two standards called Siemens units 
which he had, that caused the discrepance, and that his 
results may after all be found to agree closely with yours. 
Helmholtz proposed and the sous commission adopted a 
resolution to move (via the French Gov 1 .) for transmission 
of individual standards from one to another of persons 
who have made absolute determinations. This will be 
very valuable, but I shall try to arrange with Fr. Weber 
for an immediate interchange of standards between you 
and him. Could you send me one here, which I could 
receive by Saturday evening, or at the latest Sunday 
evening, and give to him to take away with him. That 
would settle the question, no doubt, in a few days. Or 
with very little delay there might be an interchange 
between you and him after he gets back to Zurich. He 
is himself under the impression that you are right, and so 
are Helmholtz and Wiedemann. 

Our last general meeting will probably be on Monday 
morning, and terminate the whole business of the present 
session ; but no doubt there will be another this time next 
year, and I think it is desirable there should be, because 
I think, judging from the past, good and useful work 
and conventions will be promoted by at least one other 
meeting analogous to this and to last year s one. 

Lady Thomson and I intend to be at Cambridge from 
Friday or Sat. of next week to Monday or Tuesday 
following, but I have not yet heard of the day for the 
college meeting (the statutory 29th being Sunday), and I 
do not know where we shall be staying. 

I hope you are feeling much better, and quite well again 
now. Yours very truly, WILLIAM THOMSON. 



On November 27 Lady Thomson wrote to 
Darwin to urge him to visit them : 

Sir William says you and he can settle about the 
Preface and title-page when you come. Sir William 
says he has written to ask T to come from a Friday to 
Monday (%th to I itk, if you are here at that time) to help 
to settle the question (he is writing this moment). Sir 
William has been very busy ever since he came home 
never a moment to spare ; he has dynamos, and sound 
from double and multiple sources^ such as tuning-forks > on 
the brain. [The clauses printed in italics are in Sir W. s 

In December he went to Portsmouth to see 
about the compasses of H.M.S. Polyphemus, a very 
difficult ship for compass-compensation. And on 
Christmas day he and Lady Thomson went to 
Knowsley for the annual visit to Lord Derby. 

The revision of the Natural Philosophy lasted 
on into the spring of 1883, and the designing of 
electric measuring instruments was still a heavy 
burden. In February Sir William gave a dis 
course at the Royal Institution on the Size of 
Atoms. 1 In March he communicated to the 
Royal Society of Edinburgh three papers : on 
the Dynamical Theory of the Dispersion of Light, 
on Gyrostatics, and on Oscillations and Waves in 
an Adynamic Gyrostatic System. He wrote to 
Darwin : " I have been very full of gyrostatics 
lately, partly or chiefly brought on by my Royal 
Institution lecture on Size of Atoms." To Lord 
Rayleigh he wrote for information : 

1 See p. 566 ; and Popular Lectures, vol. i. p. 147. 


Ap. ii, 1883, 

DEAR LORD RAYLEIGH I am to give a lecture at 
the Institution of Civil Engineers on Electric Units on 
the 3rd of May, and I should be much obliged if you 
will tell me if there is any later work than what I know 
already of yours, which made the B.A. unit =-98677 

I am now regularly taking the Rayleigh (or true) 
ohm as I -0134x6. A. unit, and making resistance 
coils accordingly. Also, I use now the Rayleigh (or 
true) volt as greater in the same proportion, i.e. I -01 34 x 
B.A. volt. I suppose this is very sure to be as near the 
absolute truth as can appear in anything I am doing ; 
but for the sake of my lecture I should like to know the 
very last of what you have done ; and particularly to 
know if you change the last figure from what I have. 

I am glad to hear from Darwin, who is with us just 
now, that you are so much better. I hope you will not 
be troubled by any return of the enemy ; but you must 
not work too hard in the laboratory, or otherwise. Yours 
very truly, WILLIAM THOMSON. 

The lecture on Electrical Units of Measurement 
was given on May 3rd. The printed version in 
Vol. I. p. 73 of his Popular Lectures gives but a 
faint idea of the impression it made on the hearers. 
The lecture began by emphasizing the necessity 
in physical science of finding true principles for 
numerical reckoning and methods for measuring. 
" I often say that when you can measure what you 
are speaking about, and express it in numbers, you 
know something about it ; but when you cannot 
measure it, when you cannot express it in numbers, 
your knowledge is of a meagre and unsatisfactory 
kind." He commented on the advance made in 


electrical measurement. Ten years ago the scientific 
instrument-maker scarcely knew whether the con 
ductivity of his copper coils was within 60 per cent 
of that of pure copper ; and the professors did not 
know the resistances of the electromagnets in their 
laboratories. Now all that was changed, and clerks 
and junior assistants could measure the resistance 
of wires more accurately than you could measure 
the length of ten feet. Few lecturers, not even 
himself, knew the capacity of the Leyden jars on 
his lecture-table ! As to electromotive force, " we 
have scarcely emerged one year from those middle 
ages when a volt and a Daniell s cell were considered 
practically identical." And this advance was due to 
commercial requirements. 

There cannot be a greater mistake than that of looking 
superciliously upon practical applications of science. The 
life and soul of science is its practical application ; and 
just as the great advances in mathematics have been 
made through the desire of discovering the solution of 
problems which were of a highly practical kind in 
mathematical science, so in physical science many of 
the greatest advances that have been made from the 
beginning of the world to the present time have been 
made in the earnest desire to turn the knowledge of the 
properties of matter to some purpose useful to mankind. 

He then referred to the growth of the absolute 
system of measurement ; to the British Association 
Committee of 1861, and the "ohm " which resulted 
from its eight-year-long labours ; to the Paris Con 
ference of 1882, and the researches of Weber, of 
Siemens, and of Lord Rayleigh and Mrs. Sidgwick, 

VOL. II p 


leading to the latest accepted values. Then with a 
passing rap at British units he went off into a 
disquisition as to the importance of absolute units 
based on universal gravitation and on the semi- 
period of an infinitesimal satellite ! The better to 
realize an absolute system of measurement, and to 
detach their ideas from terrestrial limitations, he asked 
his hearers to imagine a scientific traveller roam 
ing through the universe. " For myself," he said, 
"what seems the shortest and surest way to reach 
the philosophy of measurement is to cut off all 
connection with the earth." And so he supposed 
his scientific traveller to have lost his watch, his 
measuring rod, and his tuning-fork, and to be 
trying to recover the values of the centimetre 
and the mean solar second ; the former, by the 
aid of a diffraction grating (which he himself must 
rule on glass) and the spectrum of the sodium flame 
seen through it ; the latter, by making a re- 
determination of the ohm, or by experiments on 
electric oscillations with a coil and a condenser ! 
Well do some of those present remember that 
bewildering excursus. After thus filling an hour 
and a quarter, he announced that he had only 
reached the threshold of the subject, and must 
now commence the consideration of electrical units. 
He referred to the B.A. reports ; recalled how he 
had himself constructed sets of conductance coils 
(mho-boxes) thirty years before ; praised the " magical 
accuracy" of Joule, whose refined thermal experi 
ments had first raised a doubt on the value of the 


B.A. unit. He ended by naming the things still 
needed to perfect the system of absolute measure 
ment, and recommended the audience to purchase 
Everett s book on Units, price three and sixpence! 
May was spent partly in London and partly in 
festivities at Cambridge. Before going north to join 
his yacht Sir William wrote to Lord Rayleigh : 

I have nothing, at all events as yet new, in the way of 
dynamos, and I am afraid most of my other practical 
affairs, integrators, domestic volt-meters, mho-meters, regu 
lators, etc., are also in the future tense or paulo-post- 
futurum. (Can there be such a tense, or do I misremember 
my grammar ?) 

To von Helmholtz, who had the previous year 
been ennobled by the German Emperor, he 
wrote : 

June 17, 1883. 

DEAR HELMHOLTZ A note I have from Lockyer 
seems to imply that you have not yet received a copy of 
the second part of the new edition of Thomson and Tait s 
Natural Philosophy. I directed a copy to be sent to you, 
immediately on the publication of the book ; but I shall 
write again to the publishers to make sure that they send 
it, if they have not done so already. 

I hope you received in due time the 2nd edition of 
the first part, and also the first volume of my collected 
Mathematical and Physical Papers. I directed the pub 
lishers in each case to send you a copy immediately on 

We have now been afloat and at home on board the 
Lalla Rookh for a fortnight, with a weekly visit to the 
Laboratory, and we shall be oscillating between the two 
L s for the greater part of the summer. Will you not 
come and have a cruise with us, either in July in the 


Solent or in August in the Clyde ? If you could come 
to us in August or September you would find us with 
one foot on shore occasionally, at " Netherhall," a house 
we have built for ourselves at Largs (but now I remember 
you saw it), but which the superior attractions of the 
Lalla Rookh keep us from living in so much as we would 
otherwise like. The British Association meets on the 
i pth of September at Southport (near Liverpool), and if 
you would come to us in September early enough to have 
some good sailing first, we might go there together. We 
hope Mrs. Helmholtz will be able to come with you, and 
you must tell her not to be deterred by the idea of the 
yacht if she is not a good sailor, as any time after the middle 
of August the house on shore will always be available. 

In the Laboratory I have been greatly occupied with 
electric measuring instruments, chiefly for practical pur 
poses connected with electric lighting. One that I hope 
to have going very soon a gyrostatic current integrator, 
or " coulomb meter " I think would interest you. I 
have also a new electrometer and some arrangements of 
galvanometers to give moderately accurate absolute deter 
minations through very wide ranges. I need not tell you 
about them now, however, as I hope you will come and 
see them all. 

Lady Thomson joins in kind regards to you and Mrs. 
Helmholtz, and I remain, yours always truly, 


In the summer of 1883 Sir William took his 
brother James and his wife and two daughters for a 

On coming on board the ladies were amused to 
find that each of the two learned professors had pro 
vided himself with a copy of Jack Brag at the rail 
way book-stall, and had brought it with him as light 
literature to read on the yacht. The two brothers 
had long interesting- talks, interspersed with reading 


aloud Jack Brag\ and there were pleasant walks 
when the yacht was at anchor. The cruise was 
delightful ; there was good sailing weather, though 
one of the days was so stormy as to make it 
advisable to seek shelter behind the Otter Spit in 
Loch Fyne. 

A letter from Lady Thomson to Professor 
Darwin, dated from Otter Bay, Loch Fyne, on 
June 24th, takes up the tale of their doings. 

. . . We have been on board the Lalla Rookh ever 
since we returned from London at the beginning of the 
month, sailing about the Clyde and taking a weekly run 
to Glasgow for a few hours at White s and in the 
Laboratory. We expect to go to London again for a 
few days early in July, and we shall probably let the 
yacht sail round to Portsmouth to wait for us. If you 
are inclined to offer us a visit in the L.R. when we are 
in the Solent, we shall be very glad. We hope to be at 
Netherhall for about a month, till the ipth Sept., when 
we go south for the B. A., and then for Sir Wm. to give his 
address in Birmingham as President of the Birmingham 
and Midland Institute ; and then we go off to Vienna, 
where he is one of the Government Delegates to the 
Electrical Exhibition, so our time at Largs will be limited 
to about a month from 2Oth August to ipth Sept. I 
tell you all this that you may know our movements, and 
may plan to come to us accordingly. . . . 

After going to Ireland for the opening of the 
Portrush electric railway, Sir William and Lady 
Thomson went to Southport for the British Associa 
tion meeting on September iQth. He read two 
papers, one on Gyrostatics, and one on Asymmetry 
of Crystals. 


The Address to the Midland Institute at 
Birmingham, on October 3rd, was on the Six 
Gateways of Knowledge. It dealt with the per 
ception of the senses, the sixth sense in his 
enumeration being the sense of temperature, which 
he carefully discriminated from the sense of force 
or tactile sense, with which it is usually confounded. 

Dealing with the possibility of a seventh sense 
a magnetic sense which, in spite of the failure of 
all attempts to detect it by powerful electromagnets, 
he still considered just possible, he took the 
opportunity to denounce " that wretched supersti 
tion " of spiritualism. The section dealing with 
sound and music, and with the mathematical view 
of sound, is of extreme interest. Mathematics he 
averred to be etherealized common sense, as logic 
is etherealized grammar. 

After Birmingham came the visit to the Electrical 
Exhibition at Vienna. Sir William made experi 
ments there with M. Abdank on batteries, and 
admired Ganz s large alternator. Returning via 
Berlin he spent four days with von Helmholtz, 
and reached England on November 3rd. 
r This year he presented to his old college, Peter- 
house, in commemoration of the 6ooth anniversary 
of its foundation, a complete installation of electric 
light. The plant consisted of a small Lancashire 
boiler and horizontal engine, driving a Ferranti 
alternator and a Siemens exciter. It was used for 
the first time on the Queen s birthday, 1884; and 
after twenty-five years the same machines are still 



doing excellent work. Sir William also designed 
the needful switches and details for pendants and 
other fittings. The cost to him of this gift cannot 
have been less than ^2000, and is believed to have 
been more. 

On November 2 1 Sir William wrote to Darwin 
from Glasgow that he was going to Cambridge to 
stay a few days at Peterhouse to settle details about 
the electric lighting. 

The sad news of the death of Sir William Siemens 
came on us like a thunderbolt. We had travelled home 
from Vienna together, stopping in Berlin on our way, and 
I had just three days before his death answered a letter 
he had written me (now, as it appears, after he had 
been suffering from the fall), in which he said nothing 
of being ill, and was full of new plans for meeting at 
Sherwood, Cambridge, etc. It is a very great distress 
to us. 

And on the 26th Lady Thomson wrote : " We 
have been at Sir W. Siemens s funeral to-day. His 
death has been a great grief to Sir William so 
much so that I felt I must come up with him and 
look after him." An obituary notice by Thomson 
of his friend appeared in Nature of November 29th. 

In presenting to Sir William Thomson the 
Copley Medal on November 30, the President of 
the Royal Society, Professor Huxley, pronounced 
the following eulogium : 

The number, the variety, and the importance of Sir 
William Thomson s contributions to mathematical and 
experimental physics are matters of common knowledge, 
and the Fellows of the Society will be more gratified 


than surprised to hear that the Council have this year 
awarded him the Copley Medal, the highest honour which 
it is in their power to bestow. 

Sir William Thomson has taken a foremost place 
among those to whom the remarkable development of 
the theory of thermodynamics is due ; his share in 
the experimental treatment of these subjects has been 
no less considerable ; while his constructive ability in 
applying science to practice is manifested by the 
number of instruments, bearing his name, which are at 
present in use in the physical laboratory and in the tele 
graph office. 

Moreover, in propounding his views on the universal 
dissipation of energy and on vortex motion and molecular 
vortices, Sir William Thomson has propounded concep 
tions which belong to the prima philosophia of physical 
science, and will assuredly lead the physicist of the future 
to attempt once more to grapple with those problems 
concerning the ultimate construction of the material 
world, which Descartes and Leibnitz attempted to solve, 
but which have been ignored by most of their suc 

Returning home, Sir William wrote to Lord 
Rayleigh, urging him to take up electrostatic 
measurement. There was further correspondence 
between them through the winter on electrical 
units, as another International Conference was 
fixed in Paris for April 28, 1884. Moreover, Lord 
Rayleigh had been chosen as President of the 
British Association for the meeting to be held 
in Montreal in August 1884, and Sir William 
Thomson was once again asked to preside over 
the Mathematical and Physical Section. The 
following selections from the letters of this time 
deal with some of these matters : 


Jan. 20/84. 

DEAR LORD RAYLEIGH I send you the " Units " 
lecture and two others. 

Many thanks for the information about Weber and 
the spinning method. The apparatus used by the B.A. 
Committee was made for me by White in Glasgow, and 
put to some rough tests by myself before it was put into 
the hands of the Committee, whose first reported experi 
ments with it must have been made about January 1863. 
I don t know if anything of it was published before Aug. 
1863, but I think it must have been in 1861 or early in 
1862 that I set about having it made. If I find any 
notice of it prior to Aug. 1863 (or to Weber s date) I 
shall tell you, but it is not a matter of importance. I 
shall look for Weber s paper, however, immediately. 
I had never seen it and only knew of the Electro- 
dynamise he Maasbestimmungen. I shall be greatly 
interested to hear more of your silver weighings and 
further conclusions as to a standard for E.M.F. I suppose 
from your letter that you find Clark s all trustworthy to 
less than -2 or -3 per cent ? 

I am working hard at potential galvanometers to serve 
up to 200 volts, and electrometers for above that ; and 
mho-meters to serve for practical current-meters, also 
integrators and regulators. As to electrometers, I had 
made the cylindric form roughly and heavily, which for 
absolute determinations has, as you say, the advantage of 
requiring no guard-border. But I thought the small flat 
disc easier to realize for work in potentials so small as 
200 volts. 

I hope you have been profiting by your stay in Bath, 
and that you are now feeling much better. Yours very 

P.S. Have you decided when and how you go to 
Montreal ? 


2.\st Feb. 1884. 

DEAR LORD RAYLEIGH I should be very glad to 
hear from you how you use the Clark cell to get such 
constant results in respect of potential. I find that it 
varies enormously, and shows great polarization when 
allowed to flow through as great a resistance as 15,000 
ohms. I could not use it with any good results for my 
potential galvanometers, whether by a zero method such 
as that of Poggendorff or other, unless it were confined to 
showing on an electrometer its potential, or the equality 
of its potential to that of some point of one of my 
circuits. Believe me, yours very truly, 


P.S. I am getting results that promise to come 
within ^ per cent by a new form of Daniells (I described 
it in the Telegraphic Review and the Electrician about 3 
weeks ago). I was sorry not to be able to look for you 
in the Laboratory when I was in Cambridge one day 
about a fortnight ago. 

March 5/84. 

DEAR LORD RAYLEIGH The Cunard Company have 
offered Lady Thomson and myself free passage to 
America and back in one of their ships. So we leave, in 
the Aurania if possible (that is if times suit), about the 
end of July. I hope this may also suit you and Lady 
Rayleigh. It will be very pleasant if we can make the 
voyage together. 

As to my new form of standard Daniells, I have been 
getting excellent results ever since I wrote to you last. 
Here is a specimen of some got to-day in a new 
departure in the way of systematic short-circuiting. . . . 

My newest long-range potential galvanometer is, when 
no resistance is added to its circuit, to have, I think, 
exactly rooo R[ayleigh] ohms for its resistance. Its 
constant I shall probably determine by 5 of the new 
cells in series. I am, however, also making new forms 
of electromagnetic standardizers (on the fundamental 



principle of Weber s electrodynamometer), which are 
promising well, and may possibly in practice prove as 
accurate as the standard cells. 

I hope in a few days to be able to send you a 
specimen of my new standard cell. I have been waiting 
to do so till I should get the plan fixed. Now I am 
only waiting till I can get a few cells made on a plan 
which I am fairly satisfied with as fixed. Yours always 
truly, W. THOMSON. 

Ap. 25/84. 

DEAR LORD RAYLEIGH We set out to-night for 
Paris and hope to arrive to-morrow evening. H6tel 
Chatham, Rue Daunou, will be our address. I should be 
very glad to hear from you your latest results, or to know 
that there is, in the hands of some member of the Congress 
in Paris, a printed paper, or papers, describing your work 
and results, also Glazebrook s, as to ohm specially, but also 
volt and electrochemical equivalent. A line or two from 
you to me, telling me what you would now take as the 
most probable value of the B.A., and the length of the 
column of mercury that, with i m / m section, at o cent., 
has resistance equal to the true ohm. 

I have an electrodynamometer (current standardizer) 
in progress, to give very good sensibility with current of 
5 amperes through it ; but fairly sensitive, I hope, with 
from 2 to 3 am. I hope next week, or at all events within 
a fortnight from now, it will be ready to be sent to you. 
I hope these strengths are not too great to be convenient 
for measurement by your standard (though I remember 
you said about of an amp.). The resistance of my new 
inst t- will be only about 8 x io 7 ( = o8 ohm), so it will 
be very easy to get a strong enough current through it to 
give good sensibility, but I am afraid you may not get so 
strong a current easily in series with yours, which has far 
higher resistance. 

Excuse this scrawl, written in a Senate meeting at which 
I am assisting ! Yours truly, WILLIAM THOMSON. 


On June 22 he wrote again : 

I have a very promising table of expts. from my 
laboratory this morning, which seems quite to promise one 
very simple ampere-gauge with a range of I to 100 

The last week of June was spent with Sir 
Anthony Hoskins on board H.M.S. Hercules, with 
the reserve squadron, on a cruise to Heligoland and 

the Orkneys. 

Aug. 4. 

DEAR LORD RAYLEIGH Please don t forget to tell 
the printers to send me your Address. I leave Glasgow 
for L pool on Friday, and L pool on Saturday in the 
Servia ; and I hope to receive it before I leave. (Will 
you let me have a proof though not finally corrected, if a 
finally corrected one cannot reach me in time.) We are 
very sorry you are not coming with us in the Servia. 

I have made great advance (I think) in standard- 
current measures, for all currents from 10 milliamperes 
to 1000 amp s> (or as many more as are to be measured 
in any case). I shall tell you about it when we meet. 
It is founded on the tendency of a ball or cube of soft 
iron towards places of greater force (c x rate of variation of 
R 2 in any direction = the component force in that direction, 
R being the " resultant magnetic force " of the field). This 
action, I find, is not sensibly influenced by magnetic re- 
tentiveness, and is very closely in proportion to the 
square of the strength of the current, through the whole 
practicable range. Yours very truly, 



Aug. 6/84. 

DEAR LORD RAYLEIGH Many thanks for the proof 
of your Address. I am very sorry, however, that I have 
put you to the trouble of sending me one with some of 



your corrections written on it. I thought the printers 
could have sent me one or I would have waited. I 
enclose you a copy of my Section A address. I hope the 
meeting, and generally your visit to America, will prove 
rather a rest and refreshment to you than a fatigue, but I 
shall remember what you say, should there seem to be 
any occasion for guarding against overwork. I hope the 
press-men (interviewers or others) will not prove a great 
plague ! 

I am a good deal troubled about the new milliampere- 
meter just now, but I hope to-morrow I may see things 
going better about it in the laboratory. Believe me, 
yours very truly, WILLIAM THOMSON. 

These letters show how greatly Sir William s 
time was taken up with his instruments. Von 
Helmholtz, too, had been struck with this earlier 
in the spring when paying a round of visits to 
his English friends, Tyndall, Huxley, Roscoe, and 

He found Sir William absorbed in regulators and 
measuring apparatus for electric lighting, and for 
electric railways. To Frau von Helmholtz he 
wrote : 

On the whole, however, I have an impression that Sir 
William might do better than apply his eminent sagacity 
to industrial undertakings ; his instruments appear to me 
too subtle to be put into the hands of uninstructed work 
men and officials, and those invented by Siemens and 
von Hefner Alteneck seem much better adapted for the 
purpose. He is simultaneously revolving deep theoretical 
projects in his mind, but has no leisure to work them 
out quietly ; as far as that goes I am not much better off. 

Then immediately he adds : 

I did Thomson an injustice in supposing him to 
be wholly immersed in technical work ; he was full of 


speculations as to the original properties of bodies, some 
of which were very difficult to follow ; and, as you know, 
he will not stop for meals or any other consideration. 

Sir William had indeed weighty matters on hand. 
He had agreed, more than a year before, to give in 
Baltimore, in the autumn of 1 884, a course of lectures, 
as will be related in the next chapter ; and he had 
chosen as the topic molecular physics, in relation 
to the wave-theory of light. His address for the 
British Association at Montreal was also in process 
of evolution, and the ever-haunting idea of a kinetic 
explanation of the properties of matter was again 

The title of the Montreal address was " Steps 
towards a Kinetic Theory of Matter." Beginning 
with the molecular processes that go on in a gas 
according to the kinetic theory, and throwing out 
a suggestion that the condition for equality of 
temperature between two gaseous masses is equal 
average amounts of kinetic energy per molecule, he 
discussed the nature of the repulsive motion which 
apparently characterises the action of free molecules 
during the impact at every collision. We must 
regard each molecule as being either a little elastic 
solid or else a configuration of motion in a continuous 
all-pervading liquid. The first step toward a mole 
cular theory of matter had been this very kinetic 
theory of gases, of which all we had to the present 
time would be equally true if a gas consisted 
mechanically of little round, perfectly elastic solid 
pieces of matter flying about. But the difficulty 


remained unsolved that if each molecule is a con 
tinuous solid the whole translational energy must 
ultimately become transformed into vibrational 
energy. Even apart from this difficulty, the 
elasticity of a gas was, on this theory, only explained 
by making an assumption much more complex and 
more difficult to explain the elasticity of a solid. 
This led him on to the next possible step, the 
possibility of explaining kinetically that property 
of matter which we call elasticity, as being itself 
a mode of motion. He therefore restated the 
principal points of his former lecture (see p. 743 
above) on elasticity, and again described the 
gyrostatic model by which he imitated a common 
spring balance by use of fly-wheels, themselves 
devoid of elasticity. Another kinetic model could 
be imagined having irrotational circulation of a 
perfect liquid through apertures in solids immersed 
in it. Vortex rings and coreless vortices, under 
conditions consistent with stability, could also 
present phenomena like elasticity, the elasticity 
being due in reality to motion. 

To the sectional meetings at Montreal Sir 
William made two communications : on a gyrostatic 
working model of the magnetic compass ; and on 
safety-fuses for electric circuits. 

The Montreal meeting over, many of the 
scientific men in attendance travelled south, via 
Niagara Falls, to Philadelphia, where an electrical 
exhibition was being held, and where also the 
American Association for the Advancement of 


Science was holding its session. Here Sir William 
read a paper (the title only appears in the Proceed 
ings) on the distribution of potential in conductors 
experiencing the electromagnetic effects discovered 
by Hall. 

While in Philadelphia Sir William was induced 
to deliver, in the Academy of Music, on September 
29, a popular lecture on " The Wave Theory of 
Light." This lecture, 1 as all who were present will 
remember, gave an excellent summary of points in 
the elementary theory of light, and touched upon the 
problem of the propagation of waves in the ether ; 
elucidation being afforded by a model of a molecule 
embedded in jelly ; while the mobility of matter 
through the ether was illustrated by the ready, if 
slow, passage of leaden bullets by their own weight 
through shoemakers wax. The lecture was enlivened 
by several characteristic passages : 

" You in this country are subjected to the British 
insularity in weights and measures." " I hope the teaching 
of the metrical system will not be let slip in the American 
schools any more than the use of the globes." " I look 
upon our English system as a wickedly brain-destroying 
piece of bondage under which we suffer." " The lumin- 
iferous ether ... is the only substance we are confident 
of in dynamics. One thing we are sure of, and that is 
the reality and substantiality of the luminiferous ether." 
" Some people say they cannot understand a million 
million. Those people cannot understand that twice two 
makes four. That is the way I put it to people who talk 
to me about the incomprehensibility of such large numbers. 
I say finitude is incomprehensible, the infinite in the 

1 Reprinted in Popular Lectures, vol. i. p. 300. See also p. 1035 infra. 



universe is comprehensible. . . . What would you think 
of a universe in which you could travel one, ten, or a 
thousand miles, or even to California, and then find it 
come to an end ? Can you suppose an end of matter or 
an end of space ? The idea is incomprehensible." 

From Philadelphia Sir William and Lady Thom 
son travelled on to Baltimore for the lectures which 
he was to give at the Johns Hopkins University. 

Lady Thomson wrote on October yth from the 
Mount Vernon Hotel, Baltimore, to Professor 
George Darwin : 

I hope you had a good voyage home. We have had 
nothing but hot weather since you left. We have never 
been able to keep in cool regions. We were two days in 
Boston and Cambridge, which we enjoyed very much. 
The only cool days we have had were at Southampton in 
Long Island, Sag Harbour and Shelter Island, on our way 
to Boston. We had to come back to Philadelphia on our 
way here, as Sir William had promised to give a lecture 
there on the 2 9th on the " Wave Theory of Light." 

We came on here on the 3Oth, and we have been quite 
glad to be quiet in one place, but the heat continues very 
trying at night as well as in the day. Everything is hot 
and dry and parched. The leaves of the trees are falling 
instead of colouring, and the perpetual blue sky is quite 
fatiguing ! We are very tired of this hot weather 
thermometer rarely below 80. Sir Wm. is enjoying his 
lectures, I think, as much as his audience. They are 
going on capitally, and he has a most eager, interested 
audience of about 60 or 70, which is double what they 
expected, many of them Professors from all parts of the 

But the Baltimore Lectures constitute so not 
able an episode that they require a chapter to 




A UNIQUE episode in the career of Lord Kelvin 
was the course of twenty lectures on Molecular 
Dynamics which he delivered at Baltimore in the 
late summer of 1884. At a time when most of the 
American Universities were mere High Schools, 
with little or no post-graduate instruction, the 
Johns Hopkins University of Baltimore stood out 
alone in realizing that the glory of a university lay 
in advanced post-graduate studies and research. 
Not only did she fill her chairs with the leaders 
of thought, but she sought to free them from 
academic routine and administrative drudgery that 
they might the better labour for the few ripe 
students capable of high instruction. And to this 
she added the function of inviting European pro 
fessors of distinction to give short courses in the 
lines of their own individual work. An invitation 
to deliver such a course was addressed to Sir 
William Thomson in 1882 : 




Aug. I3//&, 1882. 

DEAR SIR WILLIAM THOMSON I am very sorry that 
so long an interval has elapsed since your kind reply to 
an overture which Professor Sylvester made to you by 
my request, in respect to your coming to Baltimore and 
delivering some lectures. I beg you to hold me responsible 
for this delay, and to exonerate him entirely. There was 
a strong possibility that I should visit your country during 
the present summer, and if I had been able to do so, a 
personal interview would have enabled me to explain to 
you some circumstances which it would be tedious to 
dwell on in writing, particularly in regard to the time 
of your coming. But as my going is postponed, I write 
to say that the warm weather is a serious obstacle to 
work at the late period which you named, and the highest 
advantages of your visit would be promoted by an earlier 
appointment, if you can possibly make one. Prior to 
April 15, and after October I, would be the periods most 
useful, and we should hope that you would lecture to 
advanced students in physics on such topics as you would 
choose yourself. If, during the winter of 82-3 or of 
83-4 you could be persuaded to visit Baltimore, I would 
at once ask the Trustees to make you a formal propo 
sition in place of this unofficial and informal letter. 
From what has been said by my colleagues, Prof 5 . Syl 
vester and Rowland, and by Prof. Wolcott Gibbs, I 
believe that the announcement of a University Course 
of lectures by you in Baltimore, on topics of your own 
choice, would give a strong impulse to the study of 
Physics in this country. I should also hope that your 
visit would be made pleasant in many ways. 

If Lady Thomson has not forgotten an American 
visitor who took lunch with you in 1875, I beg leave 
to present my high regards, and I am, dear sir, -very truly 
yours, D. C. OILMAN, 

Sir W. Thomson. President J. H. U. 


The letter is endorsed thus in Sir William s hand: 
" Rec d . Sep. 2, Netherhall. Answ d . Sep. 5, accept 
ing for Oct. 1883, cond 1 . on permission to defer, by 
notice not later than July 1/83, to Oct. 1884." The 
response which follows was handed to Prof. Rowland 
for delivery to Sir William, whom he expected to 
meet in Paris : 

Oct. 12, 1882. 

DEAR SIR I have the pleasure of replying to your 
note of Sept. 6 by entrusting these lines to the hand of 
my colleague Prof. Rowland, who hopes to see you soon 
in Paris, and to talk over with you the subject of your 
proposed lectures. I beg leave to assure you that your 
acceptance of our overtures has given great pleasure to all 
of our company who have heard of our correspondence. 
We hope it will prove to be possible for you to come to 
us in the autumn of 1883, but if not, the welcome will be 
in store for you in 1884. 

This is an unofficial note. I hope in a few days (after 
their meeting, Nov. 6) to send you a formal note from 
our Trustees. Meanwhile I am, dear sir, yours with high 
regard, D. C. OILMAN. 

{November, 1882]. 

DEAR SIR My colleague, Professor Rowland, has 
returned from the Electrical Congress, and I am extremely 
sorry to find that he did not deliver the enclosed letter, 
nor have any conversation with you in respect to your 
proposed visit. 

I have been formally requested by the authorities of 
the University to invite you to come here and lecture at 
any time in the course of the next academic year con 
venient to you. We are somewhat at a loss as to what 
pecuniary compensation to offer you for this service. 
Supposing that you could hardly be persuaded to stay in 


Baltimore more than a month, the Committee proposed 
that I should offer you your travelling expenses to and 
from Glasgow, and the sum l of $ I ooo. 

Allow me to repeat the assurance that we will do all 
in our power to make your visit pleasant, and we believe 
that your influence in the promotion of science in this 
country, by such a visit to this University, would be very 
strong, and would extend far beyond the immediate com 
pany of your hearers, and far beyond the period of your 
visit. I am, dear sir, yours with high regard, 


Sir W. Thomson, F.R.S., etc. 

Lord Kelvin s own account of the matter is 
given in his preface to the printed volume of 1904 : 

Having been invited by President Oilman to deliver 
a course of lectures in the Johns Hopkins University, on 
a subject in Physical Science to be chosen by myself, I 
gladly accepted the invitation. I chose as subject the 
Wave Theory of Light, with the intention of accentuat 
ing its failures ; rather than of setting forth to junior 
students the admirable success with which this beautiful 
theory had explained all that was known of light before 
the time of Fresnel and Thomas Young, and had pro 
duced floods of new knowledge splendidly enriching the 
whole domain of physical science. My audience was to 
consist of professional fellow-students in physical science ; 
and from the beginning I felt that our meetings were to 
be conferences of coefficients, in endeavours to advance 
science, rather than teachings of my comrades by myself. 
I spoke with absolute freedom, and had never the slightest 
fear of undermining their perfect faith in ether and its 
light-giving waves by anything I could tell them of the 
imperfection of our mathematics ; of the insufficiency or 
faultiness of our views regarding the dynamical difficulties 
of ether ; or of the overwhelmingly great difficulty of 
finding a field of action for ether among the atoms of 

1 [The sum eventually agreed upon was ^400.] 


ponderable matter. We all felt that difficulties were to 
be faced and not to be evaded ; were to be taken to heart 
with the hope of solving them if possible ; but at all events 
with the certain assurance that there is an explanation 
of every difficulty, though we may never succeed in find 
ing it. 

The lectures were delivered to an audience of 
twenty-one regular attenders, including some of the 
first physicists of the day, as may be seen from a 
few of the names : 

Lord Rayleigh (England) ; H. A. Rowland 
(Baltimore, Md.) ; Eli W. Blake, jun. (Providence, 
R.I.); Cleveland Abbe (Washington, B.C.); Albert 
A. Michelson (Cleveland, Ohio) ; Fabian Franklin 
(Baltimore) ; Arthur S. Hathaway (Baltimore) ; 
George Forbes (England) ; Henry Crew (Wil 
mington, Ohio) ; Louis Duncan (Baltimore) ; A. T. 
Kimball (Worcester, Mass.); Arthur L. Kimball 
(Baltimore); T. C. Mendenhall (Columbus, Ohio); 
Edward W. Morley (Cleveland, Ohio); R. W. 
Prentiss (Baltimore), etc. There was also a con 
siderable number of casual attenders. 

The course began on October i, and ended on 
October 17. The lectures were either at 3.30 P.M. 
or at 5 P.M. ; on five days at both times. Generally 
each lecture was divided into two parts, with a 
ten minutes interval, during which the lecturer 
chatted with his students. From the first Sir 
William adopted an unconstrained conversational 
style, treating his hearers rather as fellow-workers 
in the problems under investigation than as an 
audience to be addressed ex cathedra. They, in 


their turn, worked for him by hunting up references, 
searching the University library for books, and 
tabulating solutions of problems ; informally consti 
tuting, as he himself jokingly suggested, an arith 
metical laboratory. His " twenty-one coefficients " 
they were called by one of themselves, in pleasant 
suggestion of the twenty-one coefficients by which in 
the most general case the elasticity of a body is 

Sir William Thomson had written out none of 
the twenty lectures beforehand ; he had not indeed 
formulated a systematic skeleton of the series. Part 
of the extreme interest of the course arose indeed 
from his unpreparedness. Admitted to the very 
laboratory of his thoughts, his hearers became eye 
witnesses of his methods, his amazing intuitive 
grasp, his headlong leaps, his mathematical agility, 
his perpetual recurrence to physical interpretations, 
his vivid use of mechanical analogies, and his in 
cessant resort to models, sometimes actual, some 
times only mentally visualized, by which his meaning 
could be conveyed. His audience began to see 
that here was a man who, instead of taking at 
second - hand what other workers had found or 
written, thought things out for himself from first 
principles, making discoveries even while lecturing ; 
and enjoying the surprise of finding that some of 
the things he was newly discovering for himself 
had already been discovered and published by 
others. For instance, on page 282 * we find : 

1 The references are to the pages of the original papyrographed edition of 1 884. 


I was thinking about this three days ago, and said to 
myself, " There must be bright lines of reflexion from 
bodies in which we have those molecules that can produce 
intense absorption." Speaking about this to Lord Rayleigh 
at breakfast, he informed me of this paper of Stokes s, 
and I looked and saw that what I had thought of was 
there. It was perfectly well known, but the molecule 
first discovered it to me. I am exceedingly interested 
about these things, since I am only beginning to find out 
what everybody else knew, such as anomalous dispersion, 
and those quasi-colours, and so on. 

And again (p. 120) : 

I am ashamed to say that I never heard of anomalous 
dispersion until after I found it lurking in the formulas. 

Happily for all concerned, one of the audience, 
Mr. A. S. Hathaway, who acted as reporter, was 
not only a trained mathematician, but an expert 
stenographer. Within three months a verbatim 
report of the lectures was produced by the papyro- 
graph process in a limited edition which is treasured 
by its fortunate possessors. A graphic account of 
the lectures was also published in Nature 1 by one 
of the " coefficients," Professor George Forbes. 

The difficulties in the way of accepting the wave 
theory of light Sir William stated as four in number: 

First. Dispersion. The difficulty is to explain 
how the period of vibration of light of different 
colours can affect the velocity of their propagation 
through a medium, and can cause some colours to 
be more refracted than others. Of this phenomenon 

1 Nature, vol. xxxi. pp. 461-463, 508-510, and 601-603; March 19, 
April 2, and April 30, 1885. The author has, by the kind permission of 
Prof. George Forbes, drawn freely on these articles. 


two explanations have been offered. The first is 
that of Cauchy, who ascribed it to heterogeneous- 
ness : some of the molecules in the structure must 
have sizes not infinitely small compared with that 
of the wave-length. The second is due to Helm- 
holtz, who supposes the molecules to have a com 
pound structure such that they have natural periods 
of vibration of their own. The space occupied by 
a molecule must be filled with a substance differing 
from the ether either in rigidity or in density, or 
in both respects. Thomson preferred Helmholtz s 
view, and in his first lecture set himself to devise 
a new model molecule consisting of a thin rigid 
shell, to the interior of which masses were fastened 
by springs. Several varieties of the spring-shell 
molecule were devised during the course of the 
lectures, and models of them shown. " It seems to 
me," he summed up, " that there must be something 
in this, that this, as a symbol, is certainly not an 
hypothesis, but a certainty" (p. 12). 

Second. The Ether. Here the difficulty is in 
mentally conceiving a medium so highly rigid that 
it propagates vibrations with the enormous velocity 
of 186,000 miles a second, and yet is so perfectly 
mobile that the earth and the heavenly bodies can 
apparently sweep through it without being retarded. 
This difficulty Sir William brushed aside as " not 
so very insuperable." To him there had long been 
an explanation, drawn from the behaviour of solid 
pitch or of Scotch shoemakers wax. This sub 
stance is a brittle solid, of which you might make 


a rod that can vibrate like a rod of glass. But if 
a slab of it two inches thick is laid on the top of 
water in a glass jar twelve inches in diameter, and 
leaden bullets are placed on the top of the slab, in 
a few weeks they will be found to have passed 
right through it. The difference between the ether 
and the wax was a question of time. Let the 
luminiferous ether be looked upon as a wax which 
is elastic for excessively rapid vibrations, but capable 
of yielding to stresses that are of longer duration. 
" We do not know at this moment whether the 
earth moves dragging the luminiferous ether with 
it, or whether it moves more nearly as if it were 
through a frictionless fluid " (p. 8). If we consider 
the exceeding smallness of the period of a wave of 
light, we need not despair of understanding the 
property of the ether. 

It is no greater mystery at all events than the shoe 
makers wax. That is a mystery, as all matter is ; the 
luminiferous ether is no greater mystery. We know the 
luminiferous ether better than we know any other kind 
of matter in some particulars ; we know it in respect to 
the constancy of the velocity of propagation of light of 
different periods (p. 9). 

Luminiferous ether must be a body of most extreme 
simplicity. It may perhaps be soft We might imagine 
it to be a body whose ultimate property is to be incom 
pressible ; to have a definite rigidity for vibrations in times 
less than a certain limit, and yet to have the absolutely 
yielding character that we recognize in wax-like bodies 
when the force is continued for a sufficient time. It 
seems to me that we must know a great deal more of the 
luminiferous ether than we do. But instead of beginning 
with saying that we know nothing about it, I say that we 


know more about it than we do about air or water, glass 
or iron it is far simpler ; there is far less to know. That 
is to say, the natural history of the luminiferous ether is 
an infinitely simpler subject than the natural history of 
any other body (p. 10). 

Another striking passage from the first lecture 

In the first place, we must not listen to any suggestion 
that we must look upon the luminiferous ether as an ideal 
way of putting the thing. A real matter between us and~ 
the remotest stars I believe there is, and that light consists 
of real motions of that matter motions just such as are 
described by Fresnel and Young, motions in the way of 
transverse vibrations. If I knew what the magnetic theory 
of light is, I might be able 1 to think of it in relation to 
the fundamental principles of the wave-theory of light. 
But it seems to me that it is rather a backward step from 
an absolutely definite mechanical motion that is put before 
us by Fresnel and his followers to take up the so-called 
electromagnetic theory of light (p. 6). 

Third. Refraction and Reflexion. The difficulty 
here is of a different order. Green s equations for 
the refraction and reflexion of polarized waves of 
light do indeed approximately yield results for the 
relative amounts of light that are refracted and 
reflected at different angles of incidence ; but when 
followed up not qualitatively only, but quantitatively, 
they differ considerably from the facts. For ex 
ample, they fail to account for the almost complete 
extinction observed in the reflexion of polarized 
light at the polarizing angle. 

Fourth. Double Refraction. In this case the 

1 This passage and others of similar import led his audience to conclude 
that at that date the lecturer had never read Clerk Maxwell s book ! 


difficulty is that according to the elastic theory, when 
the medium is displaced during wave-propagation, 
the forces tending to restitution must depend on 
the plane of the distortion, whereas if the Huygens 
wave-surface is true they must depend, not on the 
plane of the distortion, but on the direction of the 
vibration. And this is inadmissible, because Stokes 
has found by minute experiment that the Huygens 
wave-surface is most accurately obeyed by light. 

The difficulties to be faced having been thus 
stated, the rest of the course was devoted to their 
discussion. But each difficulty had to be regarded 
from three points of view: (i) the propagation of 
a disturbance through an elastic medium regarded 
as a whole, or from the molar standpoint ; (2) the 
character of molecular, as distinguished from molar, 
vibration ; (3) the influence of molecules on the 
propagation of waves. Some of the lectures were 
definitely divided into two parts, one devoted to 
the molar, the other to the molecular view. 

With the second lecture began a systematic 
mathematical exposition of the equations of motion 
in an elastic solid, with their three principal dis 
tortions and three principal dilatations, and the 
twenty-one coefficients by which they are related 
in the quadratic function expressing the general 
equation of energy. With the second half of the 
lecture an abrupt change was made to consider an 
apparatus consisting of three heavy masses sus 
pended below one another by spiral springs, and 
which was shown to possess three independent 


periods of vibration, depending on the stiffnesses 
of the springs and the values of the attached masses. 
The dynamical problem presented by the apparatus 
led to the equations of motion for an elastically 
embedded molecule. In the third lecture the two 
divisions of the subject were each further elaborated. 
The treatment is intensely characteristic of Sir 
William Thomson s methods. He scorned all 
formulas (he himself always said formulas, not for 
mulae), however neat, if they merely served as 
mathematical exercises, or gained their apparent 
precision from the adoption of unwarranted assump 
tions. All his formulas must have a physical meaning, 
even if he had to load them with the symbols of 
undetermined quantities, seeming, indeed, to glory 
in the possibilities of future discoveries which lay 
behind the equations. He would write them out 
on the black-board in full, though they might have 
been left to be inferred from considerations of 
symmetry. " The expenditure of chalk," he re 
marked, " is often a saving of brains." Again and 
again he referred to the aphasia of mathematics, its 
inarticulateness to express physical ideas. "The 
old mathematicians used neither diagrams to help 
people to understand their work, nor words to 
express their ideas. It was formulas, and formulas 
alone. Faraday was a great reformer in that re 
spect, with his language of * lines of force/ etc." 
Again, after a mathematical argument, turning on 
the circumstance that the differential coefficient of 
a certain continued fraction with respect to the 


period was essentially negative, he illustrated the 
inference by drawing attention to the effect of apply 
ing a push or a pull at the end of the movement of 
one of his vibrating models, and remarked : " From 
looking at the thing, and learning to understand it 
by making the experiment if you do not understand 
it by brains alone, you will see that everything I 
am saying is obvious." Yet he quoted approvingly 
from Green the words, " I have no faith in specu 
lations of this kind unless they can be reduced to 
regular analysis " ; and he praised Stokes that he 
" speculates, in a way, but is not satisfied without 
reducing it to regular analysis." 

In the fourth lecture he dealt with the difficulty 
that in the solid elastic theory a displacement must 
give rise not only to lateral vibrations (propagated 
by shears or distortions in the medium), but also 
to a longitudinal or pressural wave (propagated in 
virtue of compressions and rarefactions in the 
medium). Yet apparently in the luminiferous ether 
there is nothing found that corresponds to this 
compressional wave. 

We ignore this condensational wave in the theory of 
light We are sure that its energy, at all events, if it is 
not null, is very small in comparison with the luminiferous 
vibrations we are dealing with. But to say that it is 
absolutely null would be an assumption that we have no 
right to make. When we look through the little Universe 
that we know, and think of the transmission of electrical 
force, and of the transmission of magnetic force, and of 
the transmission of light, we have no right to assume that 
there may not be something else that our philosophy does 
not dream of. We have no right to assume that there 


may not be condensational vibrations in the luminiferous 
ether. . . . The fact of the case as regards reflexion and 
refraction is this, that unless the luminiferous ether is 
absolutely incompressible, the reflexion and refraction of 
light must generally give rise to waves of condensation. 
Waves of distortion may exist without waves of conden 
sation, but waves of distortion cannot be reflected at the 
bounding surface of two mediums without exciting in each 
medium a wave of condensation . . . and may after all 
the law of electric force not depend on waves of con 
densation ? (p. 41). 

Suppose that we have at any place in air, or in lumin 
iferous ether (I cannot distinguish now between the two 
ideas) a body that, through some action we need not 
describe, but which is conceivable, is alternately positively 
and negatively electrified ; may it not be that this will be 
the cause of condensational waves? Suppose this, that 
we have two spherical conductors united by a fine wire, 
and that an alternating electromotive force is produced in 
that fine wire, for instance with an alternating dynamo- 
electric machine ; and suppose that sort of thing goes on 
away from the disturbance at a great distance up in the 
air, for example. The result of the work of that dynamo- 
electric machine will be that one conductor will be alter 
nately positively and negatively electrified, and the other 
conductor negatively and positively electrified. It is 
perfectly certain, if we turn the machine slowly, that in 
the neighbourhood of the conductors we will have alter 
nately positively and negatively electrified elements with 
reversals, perhaps two or three hundred per second of 
time, with a gradual transition from negative, through zero, 
to positive, and so on ; and the same thing all through 
space ; and we can tell exactly what the potential is at 
each point. Now, does any one believe that, if that revo 
lution was made fast enough, the electrostatic law would 
follow ? Every one believes that if that process be con 
ducted fast enough, several million times or millions of 
million times per second, we should be far from fulfilling 
the electrostatic law in the electrification of the air in the 


neighbourhood. It is absolutely certain that such an 
action as that going on would give rise to electrical waves. 
Now it does seem to me probable that those electrical 
waves are condensational waves in luminiferous ether ; and 
probably it would be that the propagation of these waves 
would be enormously faster than the propagation of 
ordinary light waves (p. 42). 

This notion of a pressural wave haunted the 
lectures almost to the end. In the seventeenth 
lecture, dealing with reflexion and refraction at an 
interface in a case where the forces across the 
interface are balanced, he continued : 

That leaves a clean simple problem of dynamics, and 
yet people have been working at it for fifty years and 
have left it in a very sadly muddled condition, with the 
exception of the clear, accurate, and very comprehensive 
papers of Green and Rayleigh. The thing that has intro 
duced the difficulty, and makes this a more complicated 
difficulty than the other cases, is the pressural wave. The 
pressural wave, in fact, has been the bete noir of this 
problem. I do not know how Cauchy treats the animal. 
Somehow, he introduces fallacious terms involving con 
sumption of energy. MacCullagh and Neumann killed 
the animal with bad treatment. Sam. Haughton yoked 
it to an Irish car, and it would not go. Green and Ray 
leigh have treated it according to its merits, and it has 
escaped whipping at their hands (p. 233). 

In the fifth lecture, after a preliminary dis 
cussion of the periods of vibration of one of his 
spring models, Sir William suddenly interrupted 
himself in a passage which, as corrected, runs : 

No more of this now, however. It is fiddling while 
Rome is burning to be playing with trivialities of a little 
dynamical problem when phosphorescence is in view, and 


when explanation of the refraction of light in crystals is 
waiting. The difficulty is, not to explain phosphorescence 
and fluorescence, but to explain why there is so little of 
sensible fluorescence and phosphorescence. This mole 
cular theory brings everything of light to fluorescence and 
phosphorescence. The state of things as regards our 
complex model-molecule would be this : Suppose we have 
this handle P moved backwards and forwards until every 
thing is in a perfectly periodic state. Then suddenly stop 
moving P. The system will continue vibrating for ever 
with a complex vibration which will really partake some 
thing of all the modes. That, I believe, is fluorescence 
(P. 55). 

From this there was developed a consideration 
of the question of the actual constitution of ordinary 
light. Lord Rayleigh, at Montreal, had emphasised 
the distinction between the velocity of a group of 
waves and that of the waves themselves : 

It seems to be quite certain that what he said is true. 
But here is a difficulty which has only occurred to me 
since I began speaking to you on the subject ; and I 
hope, before we separate, we shall see our way through it 
All light consists in a succession of groups. . . . Take 
any conceivable supposition as to the origin of light, in a 
flame, or a wire made incandescent by an electric current, 
or any other source of light ; we shall work our way up 
from these equations which we have used for sound to 
the corresponding expression for light from any conceiv 
able source. Now if we conceive a source consisting of a 
motion kept going on with perfectly uniform periodicity, 
the light from that source would be plane-polarized, or 
circularly polarized, or elliptically polarized, and would 
be absolutely constant. In reality there is a multi 
plicity of successions of groups of waves, and no constant 
periodicity. One molecule, of enormous mass in com 
parison with the luminiferous ether that it displaces, gets 


a shock, and it performs vibrations until it comes to rest 
or gets a shock in some other direction ; and it is sending 
forth vibrations with the same want of regularity that is 
exhibited in a group of sounding bodies consisting of 
bells, tuning-forks, organ-pipes, or all the instruments of 
an orchestra played independently, in wildest confusion, 
every one of which is sending forth its sound, which, at 
large enough distances from the source, is propagated as 
if there were no others. We see thus that light is essentially 
composed of groups of waves (p. 56). 

I want to lead you up to the idea of what the simplest 
element of light is. It must be polarized, and it must 
consist of a single sequence of vibrations. A body gets a 
shock so as to vibrate ; that body of itself then constitutes 
the very simplest source of light that we can have ; it 
produces an element of light An element of light con 
sists essentially in a sequence of vibrations. . . . One of 
you has asked me if I was going to get rid of the subject 
of groups of waves. I do not see how we can ever get 
rid of it in the wave-theory of light. We must try to 
make the best of it, however (p. 66). 

I have tried to represent a sudden start, and a gradual 
falling off in intensity. Why a sudden start ? Because 
I believe that the light of the natural flame, or of the arc 
light, or of any other known source of light, must be the 
result of sudden shocks from a number of vibrators 
(P- 95). 

One exceedingly subtle point was raised, to 
which no answer appears yet to have been given, 
viz. whether, at the commencement of the impact 
of a beam of light for, say, the first thousandth of a 
second, there will not be an initial state of things 
different from the subsequent steady state, with a 
kind of initial fluorescence, and possibly a different 
refraction or reflexion from that subsequently 


Sellmeier had deduced from Fizeau s experi 
ments that in each train of waves there was no 
serious falling off for 50,000 vibrations. Is the 
diminution of amplitude in the course of several 
million vibrations practically nil ? Possibly not : it 
was a dynamical question. Helmholtz had intro 
duced into the equations certain terms to explain 
possible diminution by viscosity. 

I must still say that I think Helmholtz s modification 
is rather a retrograde step. It is not so perhaps in the 
mathematical treatment ; but at the same time Helmholtz 
is perfectly aware of this kind of thing that is meant by 
viscous consumption of energy. He knows perfectly 
well that that means conversion of energy into heat ; and 
in introducing it he is throwing up the sponge, as it were, 
so far as the fight with the dynamical problem is concerned 
(p. 98). 

A characteristic passage indeed, showing the 
constant habit of appraising a mathematical argu 
ment by its physical bearings. But, again, the 
formulas must be studied from another point of view, 
as is shown by the following passage relating to the 
determinants of the equations of connected masses : 

Now, as to the calculations. I do not suppose anybody 
is going to make these calculations ; 1 but I always feel in 
respect to arithmetic somewhat as Green has expressed 
in reference to analysis. / have no satisfaction in formulas 
unless I feel their arithmetical magnitude at all events, 
when formulas are intended for operations of that kind 
(p. 72). . . . I should think something like an arith 
metical laboratory would be good in connection with 
class work, in which students might be set at work upon 

1 Some of them were, in fact, made by Prof. E. W. Morley during the 
course, to Lord Kelvin s great satisfaction. 


problems of this kind, both for results and in order to 
obtain facility in calculation (p. 73). 

Throughout the lectures there are frequent 
references to Lord Rayleigh s investigation of the 
polarization of light in the sky, and its blue colour, 
attributable to the presence of minute particles. 
This has a bearing on the question of density and 
rigidity of ether : 

The observed polarization of the sky supports the 
supposition (which is as much as the incertitude of the 
experimental data allows us to judge) that the particles, 
whether they be particles of water, or motes of dust, or 
whatsoever they may be, act as if they were little portions 
of the luminiferous ether of greater density than, and not 
of different rigidity from, the surrounding ether. 

By the end of the ninth lecture the spring-shell 
molecule had undergone many modifications to 
afford an explanation of anomalous dispersion and 
other optical properties. With the tenth lecture 
the propagation of waves, and the energy equations 
for waves advancing in a medium, came into dis 
cussion. In connection with this the audience was 
recommended to read the memoirs of Poisson and 
of Cauchy. " The great struggle of 1815 (that is 
not the same idea as la grande guerre de 1815) was, 
who was to rule the waves, Cauchy or Poisson ? " 
He therefore suggested to the arithmetical labora 
tory to take up the case of wave-propagation in 
which the velocity is dependent on the wave-length. 
The spring-shell molecules were again to be taken 
and put into the ether, and the question examined, 


what will be the velocity of propagation under 
various hypotheses as to the masses of the attached 
molecules, and how much it will be modified by 
their presence ? Cauchy and Poisson give only 
symbols, and occasionally numerical results : they 
do not give any diagrams or graphic representa 
tions ; it would repay any one going into the 
subject to work out graphically all varieties of the 
problem of deep-sea waves. 

At this point of the course the advance was 
made from elastic solids that are isotropic to those 
which are aeolotropic, 1 or have unequal properties in 
different directions. This led back again to Green s 
twenty-one coefficients or moduluses in all their 
generality ; and again there were new models pro 
duced to illustrate aeolotropic conditions, to facilitate 
a dynamical theory of the propagation of light in 
crystalline media. One of these was a parallelepi- 
pedal structure with eight rings at the eight corners, 
connected by cords running through the rings along 
the edges of the parallelepiped. 

Now Navier s and Poisson s theory of elasticity 
give as an essential a fixed relation between the 
compressibility and the rigidity, such that if it were 
true it would make an incompressible elastic solid 
impossible. On this the comment is : 

It is curious that they did not notice that jelly is 

1 In a later passage (p. 2 14) we find : " In a structure as a whole, properties 
are produced in virtue of the manner of the structure. In fact, all structures 
of iron-work, ties, and bracings, etc., are such that if we imagine a myriad of 
them put together built up, as it were, like bricks we should have an 
aeolotropic elastic solid." 


practically incompressible. It is a wonder that they did 
not try it, and see that it did not fulfil Poisson s ratio. 
Their mistake was due to the vicious habit in those days 
of not using examples and diagrams. In the Mecanique 
celeste you find no diagrams, nor in Lagrange, nor in 
Poisson s splendid memoir on waves (p. 129). 

Then follows a passage intensely character 
istic : 

Although the molecular constitution of solids supposed 
in these remarks and mechanically illustrated in our 
model is not to be accepted as true in nature, still the 
construction of a mechanical model of this kind is un 
doubtedly very instructive, and we could not be satisfied 
unless we could see our way to make a model with the 
eighteen independent moduluses. My object is to show 
how to make a mechanical model which shall fulfil the 
conditions required in the physical phenomena that we 
are considering, whatever they may be. At the time when 
we are considering the phenomena of elasticity in solids, I 
want to show a model of that. At another time, when 
we have vibrations of light to consider, I want to show a 
model of the action exhibited in that phenomenon. We 
want to understand the whole about it ; we only under 
stand a part. It seems to me that the test of " Do we or 
do we not understand a particular point in physics ? " is 
" Can we make a mechanical model of it ? " I have an 
immense admiration for Maxwell s mechanical model of 
electromagnetic induction. He makes a model that does 
all the wonderful things that electricity does in inducing 
current, etc. ; and there can be no doubt that a mechanical 
model of that kind is immensely instructive, and is a 
step towards a definite mechanical theory of electro- 
magnetism (p. 132). 

This use of the model as affording a mental 
picture of a system endowed with particular pro 
perties was now to be directed to elucidating the 


theory of the propagation of light through crystal 
line media. The way was not yet quite clear. 

But if the war is to be directed to fighting down the 
difficulties in the undulatory theory of light, it is not of 
the slightest use towards solving our difficulties for us to 
have a medium which will kindly permit distortional 
waves to be propagated through it, even though it be 
aeolotropic. . . . What we want is a medium which, when 
light is refracted and reflected, will under all circum 
stances give rise to distortional waves alone (pp. 141-142). 

In short, the difficulty of the compressional wave, 
which Green s theory did not exclude, was again 
cropping up. While pointing out that this difficulty 
could be disposed of by simply assuming incom- 
pressibility in the medium, and reiterating that the 
lack of any corresponding facts of observation 
proved that any such action, if it exists, must be 
exceedingly small, the lecturer affirmed his belief, 
not " as a matter of religious faith, but as a matter 
of strong scientific probability," that such waves 
exist, and that the velocity of this unknown con 
densational wave is the velocity of propagation of 
electrostatic force. 

In discussing the properties of aeolotropic solids 
Sir William Thomson referred to Rankine s nomen 
clature by which he sought to elucidate the elasticity 
of solids : 

I must read to you some of Rankine s fine words. 
. . . Any one who will learn the meaning of all these 
words will obtain a large mass of knowledge with respect 
to an elastic solid. The words " strain " and " stress "~ s 
are due to Rankine, " potential energy " also. Hear the 
grand words : " Thlipsinomic, Tasinomic, Platythliptic, 


. . . Plagiotatic,Euthythliptic,etc." (p. 161). ... I explained 
to you yesterday Rankine s nomenclature of thlipsinomic 
and tasinomic coefficients. In a certain sense these may 
be all called moduluses of elasticity. I have defined a 
modulus as a stress divided by a strain, following the 
analogy of Young s Modulus. If we adhere to that then 
the tasinomic coefficients are moduluses, and the thlip 
sinomic coefficients are reciprocals of moduluses (p. 183). 
. . . Rankine was splendid in his vigour and the 
grandeur of his Greek derivatives. Perhaps he overdid 
it, but I do not like to call it an error. We cannot all 
use his words, but we learn from them in reading his 
papers. Instead of his " platytatic " and " platythliptic " 
coefficients I use the much less grand and more colloquial 
expressions " sidelong normal " and " sidelong tangential " 
coefficients (p. 185). 

Shortly after the middle of the course a new 
model was introduced, which was immediately 
dubbed the " wiggler." A steel wire was hung 
vertically, and five or six horizontal wooden laths, 
two feet long and two inches wide, were attached 
across it one above the other. These laths were 
loaded at their ends with weights, the weights on 
each lath being smaller than those on the one above 
it. The lowest of the laths was connected to a 
bifilar pendulum by which forced vibrations of 
various periods could be impressed on the system. 
It illustrated the action of a compound loaded 
molecule when subjected to vibrations from an 
external source. By this model it was shown that 
the system possessed several critical periods, each 
corresponding to the natural period of some one of 
the successive vibrators. At the critical period for 
any one vibrator all those below it are vibrating in 


one direction, while the particular vibrator and all 
above it are moving in the opposite direction. 
The model is admirably adapted to explain absorp 
tion and also anomalous dispersion. 

And so the lectures went on from day to day 
with delightful discursiveness. Here and there a 
reference to Stokes " I always consult my great 
authority, Stokes, whenever I get a chance " 
or a hit at the " brain-wasting perversity of the 
insular inertia which still condemns British 
engineers to reckonings of miles and yards and feet 
and inches, and grains and pounds, and ounces and 
acres " or an ejaculation that " there are no 
paradoxes in science " ! Questions by the hearers 
set the lecturer off on new trains of thought. 
Discussions started at the lecture were continued 
at the supper table. The whole seemed one ani 
mated conference. But the continual discursive 
ness of the lecturer became ominous. " How long 
will these lectures continue ? " asked President 
Gilman one day of Lord Rayleigh, while walking 
away from the lecture-theatre. " I don t know," was 
the reply ; " I suppose they will end some time, but 
I confess I see no reason why they should." 

Lecture sixteen introduced the question of the 
mass of the ether. " We have not the slightest 
reason to believe the luminiferous ether to be im 
ponderable." To this in November 1899 Lord 
Kelvin added an emphatic note, " I now see that 
we have the strongest possible reason to believe 
that the ether is imponderable. . . . But is there 


any gravitational attraction between different 
portions of ether ? Certainly not. . . . We must 
believe ether to be a substance outside the law of 
universal gravitation." 

In the later lectures there was a discussion of 
the so-called rotation of the plane of polarization by 
quartz, discovered by Arago, which was explained 
by ascribing to the medium a spiral molecular 
structure ; and of the true rotation by magnetism of 
the plane of polarization, discovered by Faraday. 
These properties again were illustrated by models 
the latter effect being simulated by a new kind 
of molecule with a gyrostat spinning within the 
shell. But having thus devised a crude model Sir 
William set it at once aside : 

Why do I not go into it, and try to make it a part of 
our molecular dynamics ? I answer, because I cannot 
bring out the law of inverse proportionality to the square 
of the wave-length, which observation shows to be some 
what approximately the law of the phenomenon. Until 
a week ago, I thought that by putting a fly-wheel 
somehow or other into our molecule I could get a rotary 
effect, according to which the magnitude would vary 
according to two terms, one inversely as the wave 
length, the other inversely as its cube. . . . But, alas ! my 
results give me another law ; not more effect with greater 
frequency, but less effect with greater frequency, accord 
ing to the square of the wave-length. I therefore lay 
it aside for the present, but with perfect faith that the 
principle of explanation of the thing is there (p. 243). 

In an appendix, added November i, 1884, 
and incorporated in the stenographic Report, Sir 
William Thomson described an "improved gyrostatic 


molecule " having, within a massless spherical shell, 
two fly-wheels on an axis jointed with a ball-and- 
socket joint between them, producing a gyrostatic 
effect when the molecule is accelerated in any direc 
tion except along the axis. If one imagines minute 
gyrostatic molecules of this sort embedded in the 
ether, the influence of their rotation on the trans- 
lational motion will, if they are small enough, give 
the same law as that observed by optical experi 

Most of the following lectures were subsequently 
rewritten in later years by their author; but as 
originally given they well deserve careful study. 
The twentieth lecture, in particular, is too good 
to be lost. It began by a reference to Rankine s 
suggestion that in a crystal its inertia might be 
different for forces in different directions. This 
suggestion, for which there is no observed founda 
tion in physics, he connected with Rankine s theory 
of molecular vortices, and remarked on the sug- 
gestiveness of the title : 

Rankine was that kind of genius that his names were 
of enormous suggestiveness ; but we cannot say that always 
of the substance. We cannot find a foundation for a great 
deal of his mathematical writings, and there is no explana 
tion of his kind of matter. I never satisfy myself until I 
can make a mechanical model of a thing. If I can make 
a mechanical model I can understand it. As long as I 
cannot make a mechanical model all the way through I 
cannot understand ; and that is why I cannot get [this is 
probably the reporter s Americanism for the word "accept"] 
the electromagnetic theory. I firmly believe in an electro 
magnetic theory of light, and that when we understand^ 


electricity and magnetism and light we shall see them all 
together as parts of a whole. But I want to understand 
light as well as I can, without introducing things that we 
understand even less of. That is why I take plain 
dynamics. I can get a model in plain dynamics ; I 
cannot in electromagnetics. But so soon as we have 
rotators to take the part of magnets, and something 
imponderable to take the part of magnetism, and realize 
by experiment Maxwell s beautiful ideas of electric dis 
placements, and so on, then we shall see electricity, 
magnetism, and light closely united and grounded in 
the same system (pp. 270-271). 

If the nett result of these lectures was to leave 
the impression that the difficulties in the way of the 
wave-theory of light and in particular those con 
nected with reflexion, refraction, and double- 
refraction were still unsurmounted, it certainly 
left on the hearers no sense of despair. The 
optimism which would leave an undecided problem 
in perfect faith that the ultimate solution would be 
forthcoming in due time was as notable as the 
determination to attack the difficulties all the more 
strenuously because they were difficult. As the record 
of a piece of living intellectual effort it would be hard 
indeed to find a parallel to these twenty Baltimore 
lectures. They left their mark on physical science 
in two continents, and influenced Lord Kelvin s 
thought for the rest of his life. His own farewell 
to his audience was brief: 

I am exceedingly sorry that our twenty-one coefficients 
are to be scattered ; but though scattered far and wide, I 
hope we will still be coefficients working together for the 
great cause we are all so much interested in. I would be 


most happy to look forward to another conference, and 
the one damper to that happiness is that this is now to 
end, and we shall be compelled to look forward for a time. 
I hope only for a time, and that we shall all meet again 
in some such way. I would say to those whose homes 
are on this side of the Atlantic, come on the other side, 
and I will welcome you heartily, and we may have more 
conferences. Whether we have such a conference again 
on this side or on the other side of the Atlantic, it will 
be a thing to look forward to, as this is looked back upon 
as one of the most precious incidents I can possibly have. 
I suppose we must say farewell (p. 288). 

At a dinner-party the previous evening, given 
by President Gilman to Sir William Thomson and 
his band of hearers, the following humorous verses 
were read by one of their number, whose identity is 
sufficiently attested by the signature : 


An aeolotropic molecule was looking at the view, 
Surrounded by his coefficients, twenty-one or -two, 
And wondering whether he could make a sky of azure blue 
With platytatic a b c, and thlipsinomic Q. 

They looked like sand upon the shore, with waves upon the sea, 
But the waves were all too wilful and determined to be free ; 
And in spite of s rigidity they never could agree 
In becoming quite subservient to thlipsinomic P. 

Then web-like coefficients and a loaded molecule, 

With a noble wiggler at their head, worked hard as Haughton s 

mule ; 
But the waves all laughed and said, "A wiggler, thinking he 

could rule 
A wave, was nothing better than a sidelong normal fool." 

So the coefficients sighed, and gave a last tangential skew, 
And a shook hands with b and c and 6" and T and U, 
And with a tear they parted ; but they said they would be true 
To their much-beloved wiggler, and to thlipsinomic Q. 



Before leaving Baltimore, Sir William gave, by 
request, a lecture to students in Hopkins Hall on 
The Rigidity of the Earth. 

About a year later the twenty-one coefficients 
subscribed for one of Professor Rowland s fine 
diffraction gratings, and sent it as a present to 
Sir William Thomson. The pleasure this gave 
him is recorded in the following letter to Prof. 

T. C. Mendenhall : 

G L ASGO w, 5 th Dec. 1885. 

DEAR PROF. MENDENHALL I wrote to Prof. Rowland 
acknowledging the receipt of the grating, but I ought before 
now to have thanked all the other Coefficients for their 
kindness in giving it to me. I should feel greatly obliged 
if you would transmit to those of the Coefficients who are 
in America my heartiest thanks for their great kindness, 
and say to them that it will be a permanent memorial to 
me of the happy three weeks of 1884 when we were 
together in Baltimore. 

One of the Coefficients, Prof. Davies, is here just now 
in Glasgow, but I am sorry to say he is very unwell. . . . 

After the British Association Meeting at Aberdeen I 
was delighted to be able to show the grating to some of 
our English appreciators, including one of the Coefficients, 
George Forbes, and Lord Rayleigh (whom we may con 
sider as at all events a partial Coefficient), and to Prof. 
Fitzgerald of Trinity College, Dublin, Oliver Lodge ot 
Liverpool, Glazebrook of Cambridge, and Capt. Creak of 
the Compass Dept. of our Admiralty, who came to stay 
with us at Netherhall, our country house, for a few days 
on their way south. We had no sunlight to work with, 
but we got the double sodium line in the first and second 
spectrums from a salted spirit-lamp flame exceedingly well, 
and we were all delighted with the result. I had never 
myself seen anything like it before. 

Lady Thomson joins me in kind regards. Yours very 


On December 25, 1886, Sir William wrote to 
Professor Mendenhall, sending to the Coefficients 
a little Christmas greeting in the shape of copies 
of a series of articles on Stationary Waves in 
Flowing Water. To the last he looked back 
with unalloyed pleasure to the days spent at 



SIR WILLIAM THOMSON was now sixty years old. 
He had, as we have seen, declined in 1871, and 
again in 1879, to occupy the Cavendish Professor 
ship at Cambridge. In the autumn of 1884 it 
became known that Lord Rayleigh, who had filled 
it with great distinction since Clerk Maxwell s death, 
would not longer hold the Chair. For the third 
time overtures were made to Sir William Thomson, 
His letter to George Darwin speaks for itself: 


Nov. 20/84. 

DEAR DARWIN I am afraid it cannot be alas, alas 
The wrench would be too great. I began taking root 
here in 1831, and have been becoming more and more 
fixedly moored ever since. I have things in train here to 
allow me to make the most of my capacities for work, and 
to make a new departure such as the Cavendish La b > r - and 
Prof?- would be a life s work again. Who ever becomes 
professor must devote himself to the work an excellent 
thing for any one beginning life, or looking for a fixed 
place in scientific work. To me it could not be otherwise 
than wholly a diminution of effective work. Similar 
questions have been before me, on several occasions, since, 
in fact, the first foundation of the Cambridge Chair, and 
in some other important directions. Each time I felt 



forced to the conclusion that Glasgow was the place for 
me. I have continuously felt ever since that the conclusion 
was right : and I feel more strongly than ever that my 
work is cut out for me here, and that any change would 
be a loss, however tempting in every way the change 
might be. ... 

I am frightfully under water about work for Baltimore 
(supplements I want to send off, at the latest, next week) 
for the papyrograph of my lectures there. This has kept 
me from answering your letter about Canadian tides. I 
thoroughly agree with your letter as far as I can judge, 
but I want to look at charts and tide tables to see if I 
have anything else to suggest Next week I hope to do 
so. I hope meantime you are not inconvenienced by my 

My wife joins in kind regards to you and the Plumian 
Professorin. Yours always truly, 


On December 7 Sir William again wrote, suggest 
ing that Stokes should be urged to take the chair, 
and discussing possibilities. He added : 

I am still at high pressure for Baltimore Lectures 
report ; sending a despatch of supplement every mail. I 
am at the moment in great trouble about thin metallic 
films. The rotation of the plane of polarization due to 
magnetism in a thin translucent iron film (discovered by 
Kundt, see Phil. Mag., Oct. 84) will not come out right, 
to agree with Kerr s result for reflection at a polished pole, 
and my formula for both. I have been under torture 
nine days about this. 

On 1 2th Lady Thomson wrote to Darwin that 
they were coming to Cambridge on iQth, and this 
time to Peterhouse, because of the electric lighting 
and the impending Sexcentenary. "Sir William," 
she said, " is much exercised over the Cavendish 



Professorship. . . . My man is Professor Tait. . . . 
Sir William never goes to Edinburgh and to his 
laboratory without saying what a splendid experi 
menter he is : but he could not take it even if there 
were any chance of his getting it. The emolument 
would be an insuperable barrier. He has much 
more where he is." 

To Sylvester, Sir William wrote on December 

Till a few days ago I have been desperately hard at 
work on supplements to my Baltimore Lectures, which I 
have been sending to Mr. Hathaway to be incorporated 
with his shorthand report. I got my last despatch away 
only last Saturday, after which I felt delightfully free ; 
but of course shoals of other things came on which had 
been delayed, so I have not had much breathing time yet. 

Among these other matters were three papers 
read to the Edinburgh Royal Society, and details of 
electric lighting inventions, which form the topic of 
the following letters of December 3 and December 9 
respectively, to Professor J. A. Ewing : 

ec r . 1884. 

DEAR EWING I have been thinking over your form 
of spring for the lamp-holder, and I have come to the 
conclusion it could not be patented usefully. . . . 
Curiously enough, in connection with my flat spring 
holder for lamps, I have, in all my hanging lamps at 
Peterhouse, a spiral spring on the wire which holds the 
lamp glass, with exactly the same kind of elasticity acting, 
as you have chosen for giving the horizontal forces I want 
in the platinum rings of the lamp. My flat spring is of 
course the very simplest way of producing the forces 
required. . . . Yours truly, WILLIAM THOMSON. 


9 Dec r . 1884. 

DEAR EWING None of the patents are yet published, 
I believe, but I shall enquire about them and have them 
pushed on as soon as possible. I have dropped the 
electromagnetic safety break, because after I had put up 
20 or 30 in Peterhouse I found that the slamming of 
doors, etc., upset them. They had worked perfectly in 
my laboratory. I regret this the less, however, because 
J. T. Bottomley and I have worked out an improved 
safety fuse which is simpler and cheaper, and in ordinary 
circumstances surer than the electromagnetic safety break. 
. . . Yours very truly, WILLIAM THOMSON. 

Peterhouse held high celebration on Decem 
ber 22, 1884, of the Six - hundredth Anniversary 
of its Foundation. The evening banquet was 
graced by Prince Edward of Wales, the Marquis of 
Hartington, and many celebrated men, amongst 
them the U.S. Ambassador Mr. J. Russell Lowell, 
Mr. Matthew Arnold, and Sir William Thomson, 
himself its most distinguished Fellow. The 
eighth toast, 1 proposed by Thomson, was that 
of "Other Seats of Learning," to which Lowell 

The year was concluded with visits to Lord 
Derby at Knowsley, to Lady Thomson s brother- 
in-law, Mr (now Sir) Alexander Hargreaves Brown, 

1 The toast list was long and the banquet lasted late. Near the close, 
Professor (now Sir James) Dewar proposed the toast of " Pure and Applied 
Science," calling on Sir Frederick Bramwell to reply. Rising slowly to his 
full height, and with a twinkle in his eye, the eminent engineer thanked them, 
and explained that at this late hour of the evening the only example of applied 
science that occurred to him was the application of the lucifer-match to the 
domestic candle. Seizing a pencil, Lowell instantly wrote on the back of his 
menu the following epigram : 

Oh ! brief Sir Frederick, would that we could catch 
His happy humour, and could find his match. 


at Druid s Cross, near Liverpool, and to Mr. William 
G. Crum, Knutsford. 

Jan. i, 1885, 

DEAR HELMHOLTZ I have not yet seen the Balti 
more Lectures, but I believe they will come very soon. 
One of the Johns Hopkins mathematicians, Hathaway, 
who is also a shorthand writer, undertook to make a 
report of the lectures and to bring it out in " papyro- 
graph " ; and I had a telegram from him a few days ago 
saying it was nearly ready. I have no doubt that Mr. 
Hathaway s work will be well done, but I am afraid to 
see my part of the result ! I hope to make something 
better of it, in the course of a year or so, and to bring it 
out in a printed volume. Till this is done it may be 
advisable not to let the labour of translation be under 
taken. We enjoyed our visit to America very much 
(notwithstanding a degree of heat which, we were told, 
was "quite exceptional"; but the American climate seems 
exceptionally hot except when it is exceptionally cold). 
The Baltimore Lectures were a great pleasure to myself, 
because I had twenty or thirty most agreeable and 
interesting "coefficients," many of them from distant 
parts of the States, who came to Baltimore with leave 
of absence from their Colleges and Universities for the 
three weeks of the lectures, and I felt myself stimulated 
to an interest in the subject that I had never felt before, 
and which forced me to learn something of it of which I 
had till then been exceptionally ignorant. 

I think I have at last (since about midsummer) hit 
upon a convenient and simple plan for electromagnetic 
measuring instruments, in which the "constant" of each 
instrument will be truly constant ; or rather as nearly so 
as is the earth s mass and rotational period. I have been 
working at the thing incessantly since our return from 
America, and I hope very soon to have some instruments 
made which will be convenient for ordinary use. 

We are here spending our holidays with my brother- 


in-law W. G. Crum and his family, but return to Glasgow 
on Monday. My wife joins in kind regards to you and 
Mrs. von Helmholtz and the boys, and best wishes to you 
for the New Year, and I remain yours always truly, 


At Bangor, at the University College of North 
Wales, Professor Andrew Gray, so long assistant to 
Sir William Thomson, had, as Professor of Physics, 
organized new Physical Laboratories, and besought 
his former chief to come to the formal opening of 
them. The ceremony took place on February 2, 
1885, with an Address 1 by Sir William Thomson. 
The new laboratories which he now came to open 
had been built on the space formerly occupied by the 
stables of the Penrhyn Arms Hotel. A reference 
to p. 233, ante, will show what associations must have 
been conjured up by his visit. 

He spoke of the laboratory of a scientific man 
being his place of work, and of the history of labora 
tories ; personal reminiscences of those at Glasgow, 
and of the students who had composed his own 
volunteer corps of laboratory workers. He laid 
great emphasis on the functions of laboratories in 
the true work of a university. " In university work 
teaching and examining must go side by side, hand 
in hand, day by day, week by week, together, if the 
work is to be well done. The object of a university 
is teaching, not testing . . . and examining should 
only be part of its work, and that only so far as it 
promotes teaching. The credit of the university 
should depend on good teaching." Bangor College 

1 Printed in Popular Lectures, vol. iii. pp. 473-501. 


was not yet a university ; yet he looked forward 
hopefully to the time when it would be if not an 
independent university of itself a constituent 
college of the University of Wales. 

From Glasgow, on February 8, he wrote to Mrs. 
King :- 

I am just now, and indeed have been from the 
beginning of the session, hard at work on a new set of 
measuring instruments for electric potentials and currents, 
to meet modern practical and scientific requirements. I 
had been for four or five years trying for something of 
the kind, and getting something made and brought into 
use to partially supply the want, but it is only since last 
May that I have got on the right plan, and now I am 
just on the point of getting several different instruments 
to do, much more completely than ever, what is wanted. 
. . . We were at a beautiful concert last night a popular 
concert, crammed with working people enjoying Beethoven, 
Schubert, Weber, Mendelssohn, to the utmost, on a pro 
gramme chosen by universal suffrage of themselves. 

Though Sir William was busier than ever over 
measuring instruments, he found time to entertain 
at his house the Lord Rector of that year, who 
was no other indeed than his former colleague, 
Edmund Law Lushington, Emeritus Professor of 

Natiire of May 14, 1885, contained a review by 
Helmholtz of Vols. I. and II. of Sir William s 
Mathematical and Physical Papers. It concluded 
thus : 

Let us hope for an early continuation of this interesting col 
lection. There are still nearly thirty years to be accounted for. 
When we think of that, we cannot fail to be astonished at the 
fruitfulness and unweariedness of his intellect. 


Then Sir William wrote : 

June 18, 1885. 

DEAR HELMHOLTZ I wanted before now to write 
and thank you for the very appreciative account of my 
Reprint of Collected Papers which you gave to Nature^ 
and which we read with great interest, but was prevented 
by our unsettled life, between London, visits at Cambridge 
(Prof. Stokes) and Lord Rayleigh s, and some other friends 
in England. We came on board yesterday and slept on 
board last night, but even yet have not attained to the 
quiet and settled life of the Lalla Rookh which we have 
been looking forward to, as I must be in Edinburgh and 
Glasgow this week, and in London to give evidence before 
a Committee of the House of Commons on the proposed 
Manchester Ship Canal next week. Except for these 
disturbances we should live under a triangle of forces, 
pulling to the laboratory, Netherhall, and the Lalla Rookh y 
and having their turns of preponderance with some regu 
larity. I have a new depth-gauge to test on board, and 
had some very promising trials at our anchorage here 
yesterday evening. To-day I hope to find it working 
well, when sailing with a good breeze in deeper water. I 
am very busy in the laboratory with electric measuring 
instruments. I am making standardizers on the prin 
ciple of Faraday s law, which I worked out mathemati 
cally 35 years ago, to the effect that a globe, or any not 
too elongated piece of soft iron, experiences a force in 
the electromagnetic field. ... I have recently noticed 
theoretically, and verified experimentally, that the force 
on the soft iron in these circumstances is exceedingly 
little influenced by magnetic retentiveness. A short 
bar, or a globe, experiences very nearly the same force, 
and produces very nearly the same magnetic effect 
externally to itself, as if its inductive susceptibility were 
infinitely great I find slight effects of residual magnet 
ization if R has been very great, and I provide with the 
instrument a little reversing key. A rapid succession of 


half a dozen or a dozen reversals of the current (changes 
of sign of R) brings the force on the iron to a perfectly 
definite condition, in which I find also (as theory indi 
cated) the force experienced by the soft iron is very 
rigorously proportional to the square of the strength of 
the current by which R is produced. I believe that I can 
thus have a secondary standard for the strength of a 
current accurate to ^ / Q . . . 1 T^ 

I have also an instrument on the same principle, but 
with an inspectional scale from 80 to 170, and practical 
scale of weights, for different grades, from 5 milligrammes 
to 80 milligrs. : giving, for instance, I, 2, 4 for ratios of 
the currents corresponding to the same mark on the scale. 
. . . The movable iron is a short solid cylinder, weighing 
about I J grams, and is attracted upwards by the electro 
magnetic force. The standardizing point of this instru 
ment is 80 of its scale. I have had several of these 
made, and they promise to be very useful for laboratory 
and for practical purposes (for instance, to serve, with an 
added external resistance of 2500 ohms, for an engine- 
room voltmeter, to measure from 80 to 120 volts, or 170 
with less accuracy, on an inspectional scale). 

I am also making iron-clad magnetostatic galvan 
ometers to serve from io~ 9 of an ampere to 150 amps., 
and a hectoamperemeter (on the attraction of iron prin 
ciple, but across, not along the lines of force) to serve 
from 30 amps, to 1000 amps. I have made absolute 
idiostatic electrometers for laboratory and practical pur 
poses to serve for 400 volts to 20,000 volts, which are 
already working well. My aim is a two-branched chain 
to measure currents from io~ 9 of an amp. (i.e. a mikro- 
milliampere ! !) to a 1000 amps., and from xoirw vo ^ 
(or as much less as you please) to 80,000 volts, all con 
nected by proper standardizers and comparers, and 
susceptible (I hope) of an accuracy of ^ % in every case, 
when the requisite care is given. All these are secondary 
standards, or magnetostatic instruments adjusted by 
standardizers themselves secondary standards. For a 
primary standard of current I have made an absolute 


sine-galvanometer, which works well. I think I can rely 
on the measurements we make of the horizontal com 
ponent of the terrestrial force to ^ %, and I am sure I 
can keep the error of the sine-galvanometer well within 
this figure. For primary electrostatic standard I am now 
going on to make an attracted-disk electrometer to work 
with about 10,000 or 20,000 volts difference of potential. 
I have a simple plan by well - insulated condensers 
(arranged like the old Leyden phials " in cascade ") by 
which I can multiply an hundredfold, from 100 volts 
(measured by galvanometers and resistance coils, in 
electromagnetic measure) to 10,000 volts, to be measured 
by absolute electrometer. Thus I expect to get a satis 
factorily accurate evaluation of the number of electrostatic 
units in the electromagnetic unit, which may be more 
accurate than the measurements made hitherto. 

I am afraid I have wearied you with this long letter. 
I ought really to have waited till I could give it you 
better told, in print ; but I thought you would be in 
terested, and now I am appalled to find how much I have 
taxed your eyes. Is it possible to persuade you to come 
to Scotland in summer, and to bring Mrs. von Helmholtz ? 
You know your " swimming home " here if you will come, 
and Netherhall you know also. Tell your wife that she 
will not be required to be a moment in the Lalla Rookh 
if she does not like, and if you care to come for a sail 
with me or a cruise to a little distance the ladies will 
come or stay on shore, as they please. The British 
Association is at Aberdeen on the loth of September. 
We would, if you please, go to it, but not to be troubled 
to read papers. Yours always truly, 


In July he was cruising about the Solent. He 
wrote from Cowes on July 23 to Lord Rayleigh, 
inviting him for a cruise before he should sail north 
on August 6. 

Will you come on Saturday the ist and remain till 


Wednesday the 5th (on which day I must go up to 
London to dine with Cyrus Field at the Star and Garter, 
Richmond, in commemoration of several fifths of August 
combined 1 to make the first successes of Atlantic tele 
graphy). But we shall see two days or 2^ days of the 
Cowes Regatta, before I must leave. We may ourselves 
have a good sail on both the Monday and Tuesday, and 
the preliminary Sunday will allow a settlement of Clark 
cells and other electric subjects, to make way for hydro 
dynamics. I write in the middle of disturbances flags 
flying, guns at Spithead sounding from the distance, and 
royalties flying past in steam launches, and visitors on 
board, excuse incoherence. 

Sir William and Lady Thomson were the guests 
of Lord Aberdeen at Haddo House on the occasion 
of the British Association meeting at Aberdeen on 
September 9. At this meeting Sir William took 
part in a lively discussion on electrolysis, opened by 
Professor (now Sir) Oliver Lodge. He also read a 
paper on electric measuring instruments, and another 
on the method of multiplying potentials, of which he 
had written to Helmholtz earlier in the year. Lady 
Thomson wrote to Darwin that it was a very 
pleasant meeting, much superior to that at Montreal ; 
and invited him to come to Netherhall, where 
there was to be a party of electrical folk Captain 
Creak, Oliver Lodge, George FitzGerald, R. T. 
Glazebrook, Sir George Stokes, and later Lord and 
Lady Rayleigh. 

On September 30 Sir William wrote to Mrs. 
King :- 

Our party is now all dispersed ; the last of them, her 
brother John and his wife, having left us this morning. 

1 See pages 343, 360, and 364 supra. 


We go up to Glasgow for two days work to-morrow and 
Friday, and we set out from here on Monday morning 
for Malvern. I hope you are still enjoying your villegia- 
tura, and that you all three will bring back a good 
durable stock of health when you return home. I am 
exceedingly busy with new electric measuring instru 
ments (special ones, on which I have been hard at work), 
and a new depth recorder for my sounding machine, which 
after 9 years hitherto unavailing attempts now promises 

In October, for a change before the winter session 
should open, they went to Malvern, and then to 

For some years James T. Bottomley had taken 
over as Deputy-Professor all the less-advanced teach 
ing, so that Sir William s labours as Professor were 
much lightened. The programme for the winter of 
1885-86 shows how large a proportion of the work 
was now devolved upon him. 


Every Wednesday at 12 noon. 

A special subject is chosen in each session and treated 
mathematically : such as The Wave Theory of Light, 
Hydrodynamics, Theory of Magnetism, etc. etc. : for 
session 1885-86 the subject is Vortex Motion. 


Tuesday and Thursday at n A.M. 

Dynamics, so far as can be treated without the aid of the 

Differential Calculus. 
Monday and Friday at 12 noon. 

Dynamics with the aid of the Differential and Integral 


Examinations are conducted weekly and home Exercises given 
from time to time. 


Sir William also gave experimental lectures 
on Thursdays and Fridays, at 9 A.M., to the 
whole large class ; and Mr. Bottomley gave two 
others on Tuesdays and Wednesdays at the same 

He wrote in November to Lord Rayleigh : 

The fibre suspension for balances is doing splendidly. 
I think it is going to answer well for ordinary weighings. 
I am making a delicate balance, suspended on several 
lines of single silk fibre, which will weigh safely up to 
two grams, and will not only be very delicate, but exceed 
ingly easily used. I am also making one to weigh 
anything up to 50 Ibs., to the nearest quarter-ounce not 
refusing to act according to ozs., stones and pounds 
and perhaps you may see it in all grocers shops, or at all 
events in all enlightened grocers shops, by and bye. But 
the thing I wanted the fibre suspension for has been a 
complete success. I have got over all my difficulties with 
the milliamperemeter. Two of them keep together within 
fjj per cent. 

" Capillary Attraction " was the title of a discourse 
given by Sir William Thomson at the Royal 
Institution on Friday, January 29, 1886. This 
lecture, which is printed in Popular Lectures, vol. i. 
pp. 1-55, began with a discussion of the gravitational 
attraction between two minute portions of matter at 
very small distances apart. At a distance of one one- 
hundred-thousandth of an inch (or 250 micromilli- 
metres) their mutual attraction would be insensible. 
But at one-fifth of that distance (as estimated by 
Quincke) it would begin to be sensible. All capillary 
phenomena might be explained without assuming 
any other law than that of gravitation. He had 


shown 1 in 1862 that, provided only we may assign a 
sufficiently great density to the molecules themselves, 
heterogeneousness of structure will suffice to account 
for any force of cohesion, however great. By such 
cohesive forces- one could explain the presence of 
surface tension, acting like a contractile film of 
infinite thinness over the surface of a liquid, although 
one must not fall into the paradoxical habit of 
thinking of the surface film as other than an ideal 
way of stating the resultant effect of mutual attrac 
tion between the different portions of the fluid. 
One could even calculate from the surface tension 
the period of vibration of a dewdrop. A sphere of 
water of radius i centimetre would have a period of 
vibration of J second. He then referred to the 
explanation given by his brother James, in 1855, of 
the phenomenon, due to surface tension, known as 
the " tears " of strong wine, and to the graphic solu 
tion of a number of problems of the equilibrium 
of the surfaces of pendent drops and other free 
liquid surfaces, which problems are too difficult for 
solution by the methods of the calculus. This 
graphic solution had been carried out with great 
perseverance and ability by Professor John Perry in 
1874, when he was a member of the laboratory 
corps. These drawings were now exhibited. A 
fine experimental illustration was afforded by a 
large-scale model of a pendent drop, enclosed not 
in an ideal film, but in a real film of thin sheet 

1 Note on Gravity and Cohesion, Roy. Soc. Edin. Proc. vol. iv. p. 604, 
April 21, 1862. 


india-rubber. Suspended from the roof was a stout 
horizontal metal ring, about 60 centimetres in 
diameter, covered on its lower face by a tightly- 
stretched sheet of india-rubber. When water was 
poured in, the flexible bottom bulged downward, 
and, as more and more water was poured in, the 
form changed and elongated, just as a pendent drop 
might do. The growth of this " drop," its successive 
changes of form, with their varying stabilities and 
their vibrations when disturbed, furnished an exciting 
episode in the lecture, 1 which culminated when 
finally the elastic film gave way and the drop burst 
over the lecture table, splashing the nearer members 
of the fashionably attired audience. 

One result of this lecture was a communication to 
the Edinburgh Royal Society, on March i, of a paper 
on the magnitude of the mutual attraction between 
two pieces of matter at a distance of less than ten 
micromillimetres. In April he gave another paper 
on a new form of portable spring balance for the 
measurement of terrestrial gravity. 

1 This experiment of the dewdrop was a favourite one in Sir William s 
regular university course from early times, when his assistant Tatlock used to 
mount a ladder to pour water into it. Sir William (as Mr. Bamber, a former 
student, has narrated in Engineering) had previously drawn upon the piece of 
sheet-rubber certain lines and curved figures which, as the drop swelled up, 
changed their forms and proportions. Most enthusiastically he would point 
out these changes and write down equations of curvature on the board ; he 
himself dodging about, now standing below the drop, now returning to his 
place behind the table. Then he would go back to the drop, and poking it 
with the pointer would say : "The trembling of the dewdrop ! gentlemen." 
Meantime the drop itself was increasing in size and thinness in an ominous 
way. " More water, Tatlock. Now, gentlemen, you see how this line has 
altered. Go on, Tatlock, more water." The class awaited the denouement 
breathlessly. At last it came, the "drop" having expanded from about 
9 inches in diameter to nearly 2 feet. Fortunately the learned Professor was 
on the right side of the table, with his head not as much under the "drop" 
as usual. There was no more lecturing that day after the "drop" burst. 


On February 21 Sir William wrote to Darwin : 

I am off to London to-night to elect a professor of 
physics for Sydney, and return to-morrow night. The 
new electric measuring instruments are doing well, but 
not yet ready to give out. It has been a truly tremendous 
piece of work for me these four years. 

The following letter to Mr. (now Sir William) 
Preece tells of the electric lighting : 

ibth March 86. 

DEAR PREECE In answer to yours of yesterday I 
began electric lighting in my house in June 1881. By 
the end of that year I had 1 06 lights in my house, and 
soon afterwards I had 5 2 lights in my class-room, 1 2 in 
my Laboratory, and I o were fitted up in the Senate Room 
of the University. My lamps are Swan, 85 volt, 16 candles. 

I made a Faure battery for myself of I 20 cells arranged 
in three parallels, and used it incessantly for about 18 
months, till I found it worked to death. 

Last November I got an improved Faure-Sellon- 
Volckmar battery from the Electric Power Storage Co. 
By the accompanying copy of a letter I have just written 
to Mr. Drake, you will see how splendidly satisfactory 
this has been. I scarcely ever have the engine going, 
except during the day to charge the battery. Without 
the engine I get from the battery alone ample current for 
40 lights : when I want more than 40 lights I use engine 
and battery together in the usual manner, and then I have 
ample current for from 70 to 80 lights. Yours very 
truly, W. THOMSON. 

The next letter, to the Bursar of Peterhouse, 

brings new aspects into view : 

22.nd March 86. 

DEAR DODDS Thanks for cheque. I enclose receipt. 
The dividend is lamentably small ; but what a lesson 
the state of landed property in our region ought to 
be to Gladstone and other would-be remedialists of the 


agricultural distress in Ireland. I wonder it has never 
occurred to the great mind of Gladstone himself that 
some moderate encouragement and help towards business 
habits and arrangements between Landlords and Tenants, 
coupled with defence of honest dealing on each side by 
all the power of the empire, is the only remedy possible, 
and all the remedy that is needed, to make the best of 
bad times in Ireland as everywhere else. 

Thanks for your information about the electric light. 
I hope it is doing well, and that it will be fairly satis 
factory also in respect to economy. Have the Under 
graduates got any of the lowering lamps yet ? I think 
with a lamp that can be readily lowered down to the 
table every one will feel the single light in his room 
always sufficient and quite pleasant and agreeable for 

With kind regards to all my friends at Peterhouse, I 
remain, yours truly, WILLIAM THOMSON. 

Sir William Thomson viewed with fierce hostility 
the Home Rule Bill and the Irish Land Bill which 
Mr. Gladstone had introduced that session into Parlia 
ment. As an Ulsterman he strongly disapproved 
of both schemes, the danger of which to Ireland and 
to the Empire had been at the very outset urged 
upon him by his brother James. Hitherto in such 
part as he had taken in politics he had been ranked 
as a moderate Liberal. But now he flung himself 
with intense eagerness into the Unionist cause, 
and became a leader amongst the Liberal Unionists 
of Scotland. 

He was still trying to pick up the threads of his 
Baltimore Lectures, as will be seen by his reply 
to two of the most distinguished of his American 


CLEVELAND, OHIO, March 22, 1886. 

DEAR SIR WILLIAM You will no doubt be inter 
ested to know that our work on the effect of the 
motion of the medium on the velocity of light has 
been brought to a successful termination. The result 
fully confirms the work of Fizeau. The factor by which 
the velocity of the medium must be multiplied to give the 
acceleration of the light was found to be 0-434 in the 
case of water, with a possible error of 0-02 or 0-03. This 

agrees almost exactly with Fresnel s Formula, - . 

The experiment was also tried with air with a negative 

The precautions taken appear to leave little room for 
any serious constant error, for the result was the same 
with different lengths of tubes, different velocities of liquid, 
and different methods of observation. We hope to 
publish details within a few weeks. Very respectfully, 
your obedient servants, ALBERT A. MICHELSON. 


yd April 1886. 

for your letter of 22nd ult. I am exceedingly interested 
in what you tell me, and am more eager to see in print 
your description of your experiments. The result is 
clearly of the greatest importance in respect to the 
dynamics of the luminiferous ether and of light. 

I am working all I can (but with quite an almost 
desperate amount of interruption) to have my Baltimore 
Lectures brought out in print. I hope before the volume 
is completed to have results from you that can be in 
corporated as an appendix. 

My time is very much engaged with electric measuring 
instruments, which I have been working incessantly at for 
the last four years. I have now nearly come to a 
conclusion in respect to forms of instruments, but I have 
still a great amount to do. However, I do see daylight 
clearly now through it. 



Lady Thomson joins with me in kind regards and I 
remain, yours very truly, WILLIAM THOMSON. 

27 th April 86. 

DEAR DARWIN I scarcely think we shall attend the 
B.A. this year. I think I must take a holiday when I 
get these electric measuring instruments, which I have 
been so hard at work upon for 5 years, off my hands. 

I think colour vision would be an excellent subject for 
discussion at the B.A. I think the Electromagnetic and 
the Elastic-solid theories of light will be a very good 
subject. There would be a great deal of rubbish talked 
on that or on any conceivable subject of discussion ; but I 
think that there is more hope of some good metal flowing 
out from that than from any other crucible-full that 
occurs. . . . Yours truly, W. THOMSON. 

P.S. I hope Cambridge is going to do its best to 
stop the two Bills on second reading. Was such madly 
mischievous legislation ever proposed in the History of 
England before ? 

In May came visits to Lady Siemens at Tun- 
bridge Wells, and to Lord Rayleigh at Terling 
Place. Thomson wrote to von Helmholtz : 

May 23/86. 

DEAR HELMHOLTZ . . . I am still very much en 
grossed with electric measuring instruments. I am afraid 
I cannot now say that I am nearer than, but I think I can 
safely say that I am now as near as I thought I was, to 
satisfactory results when I wrote to you a year ago ! 
This is not much to say, but I do seem happily to see 
daylight through an affair for which I have been struggling 
without intermission for 5 years. If you see Dr. Werner 
Siemens, will you tell him that I have never sent him 
the notice I promised of the new instruments which I 
showed him in Paris two years ago, because I found them 


unsatisfactory, and that I have been working ever since to 
get something better? I little thought that an electro 
meter would be the first of the set to be got into practical 
working shape : but so it is. I enclose a notice of it 
which I have only received from the printers a few days 
ago, and I shall write to White to send it (the notice) to 
Dr. Siemens immediately. My other instruments are 
electromagnetic. The standardizing current meter of 
which I wrote to you (founded on the tendency of a piece 
of soft iron to move from places of weaker to places of 
stronger force) has done very well, and has proved very 
satisfactory in my laboratory and on our house circuit, but 
I am keeping it back, because for most purposes, if not for 
all, I have got something better an intrinsic current meter 
founded on the tendency of an oblate ellipsoid of revolution 
(about 8 mm. equatoreal and 5 mm. axial diameter) to 
place the plane of its equator along the lines of force. 
The little oblate is supported on a stretched platinoid 
wire, balanced relatively to gravity, so that it will work 
as well at sea as on land. It has given me very good 
results, within I (one-tenth) per cent of absolute accuracy, 
and will serve very conveniently for directly standard 
izing currents of from -I of an ampere to 20 or 30 

All these things have left me very little time for other 
work, but I begin now to feel a little freer, and I hope 
soon to get on with the Baltimore Lectures (preparing 
for the press, etc. etc.), which have been too long deferred. 
We are staying here for a few days with Lady Siemens. 
I have told her the news of the little grandson, which 
interests her much. She sends her kindest greetings, and 
" particularly to the little grandson." Lady Thomson 
joins in the same, and particularly to yourself and your 
wife. We return to Scotland next week for laboratory, 
Lalla Rookh, and Netherhall. Yours always, 


A postcard to Darwin deals with matters they 
had discussed two days before at Cambridge. 


Chemical energy is infinitely too meagre in pro 
portion to gravitational energy, in respect to matter 
falling into the Sun, to be almost worth thinking of. 
Dissociational ideas are wildly nugatory in respect to such 
considerations. Hot primitive nebula is a wildly im 
probable hypothesis so now it seems to me at all events, 
and it can help us nothing. Langley, I suppose trust- 
worthily, finds a somewhat greater (? 7 to 6) radiation of 
the Sun than Pouillet, whose result I took. 

W. T. Glasgow, June 6/86. 

The rejection of the Home Rule Bill was followed 
by a general election, and Sir William Thomson 
threw himself into the thick of the fray, travelling 
about the West of Scotland, speaking and presiding 
at meetings for several weeks. He combined with 
this the recreation of sailing, and visited several 
places to take part in political gatherings. 

He wrote to Tait, i6th June 1886 : 

I am too busy, not only with the election, but with 
measuring instruments and with my Baltimore Lectures, to 
be able at present to give a thought to the Boltzmann 
" sibboleth," or anything else about the kinetic theory of 

From Roshven he sent to Lord Rayleigh, on July 
1 8, a number of equations about the propagation of 
harmonic waves, one of them full of complicated 
roots. He wrote : 

The following, due to a quartette of circumstances, (i) 
release from election work, (2) bondage to Baltimore 
Lectures, (3) incessant surroundings of deep-sea waves, 
and (4) a wet Sunday, will, I think, interest you. ... It 
is a surprisingly curious formula, and what Hopkins used 
to call very prickly. . . . 


The very end of my electioneering was at Oban on 
Tuesday night, where and when Craig Sellar and I held a 
meeting of Liberal Unionists in support of Col. Malcolm 
(C), candidate for Argyllshire. There was much joy on 
board the Lalla Rookh^ happily storm -stayed at Tobermory, 
on Friday night, to hear " Majority 613 Malcolm." 
What is to be done to keep Mr. Gladstone from mischief 
after all ? We hear that it is supposed " his game is to 
discredit the government and make it appear in the eyes 
of the country that he is indispensable, and then come 
back on his own terms." ... I don t for a moment 
believe he will succeed, but there is too much reason to 
believe that is his game, and more than enough to show 
that Unionist organization must be kept up vigorously 
and Unionists must act well together in Parliament ; 
keeping AS FAR AS POSSIBLE all subjects on which, as 
conservatives and liberals and radicals, they may differ 
among themselves, until a time comes when they can be 
honourably fought out and fairly settled, which certainly 
they cannot be until the two imps of mischief, Parnell 
and Gladstone, are finally deprived of all power for evil. 
What a blessing it would be if we could have Lord 
Salisbury, Lord Hartington, Chamberlain and Jesse 
Ceilings all in one government. . . . 

Three days later, being storm-stayed at Roshven, 
he sent Lord Rayleigh some new proofs of the 
proposition that the wave-velocity is double of the 
group-velocity, and added : 

We are delighted to see one Nationalist beaten by a 
Unionist in Ireland. So if dear old Scotland behaves 
not like a fool once more, in Orkney and Shetland, we 
shall have 117! What shall we (they, I mean, Lord 
Salisbury, Hartington, Bright, Trevelyan, Chamberlain and 
Co.) do with it ? Wisely, I hope. 

Again, after three days, he sent a postcard with 
more about groups of waves, and this note : 


We leave for Glasgow to-day by rail for six days 
Laboratory and White s, and Glasgow for Portsmouth 
Saturday night Will you join us at Cowes next week to 
look for hydrodynamic problems and illustrations at the 
R.Y.C. Regatta ? 

September brought the British Association meet 
ing at Birmingham. Here Sir William read four 
papers bearing on wave -problems (see p. 748), and 
one on an instrument to measure the differences of 
gravity at different places. 

The yachting ended early this autumn, the last 
cruise being on September 30. He was very busy 
with calculations on deep-sea waves and canal waves, 
required to complete certain points promised in the 
Baltimore Lectures. Politics also made demands on 
his time, and he went over to Belfast with his brother 
James to take part in Mr. Chamberlain s Anti-Home 
Rule meeting there on October n, 1886. The last 
half of October was spent at Great Malvern, and in 
a brief visit to George Darwin at Cambridge. 

Endless patience on minute detail characterized 
Sir William Thomson s prolonged efforts to bring to 
perfection the standard electrical instruments to 
which he had set his hand nearly five years before. 
The following letter to Lord Rayleigh enables one 
to understand a little the nature of such protracted 

toils : 

tfh Nov r . 86. 

DEAR LORD RAYLEIGH Many thanks for your 
volume of Electric Measurements which I was delighted 
to find on our return here three days ago. 


I have at last realized my elastically suspended balance. 
I have one now with a strong enough elastic suspension to 
bear 80 kilogrammes, and with 2^ or 3 kilogrammes 
whole weight hung on it, it is amply sensitive to three 
milligrammes. The suspension consists of 400 parallel 
copper wires, each about o-i mm. diam. and 4 milli 
metres free in the vertical bearing part. For a convenient 
weighing balance to accurately weigh 4 to 5 kilogrammes, 
I would probably use 100 bearing wires, but of platinoid 
instead of copper, possibly with 5 to 10 cms. lengths in 
the vertical bearing parts, and I would hang the weight 
pans from one end of the balance also by fine wires instead 
of knife edges. From what I have seen I am perfectly 
sure I could easily weigh with it 4 kilogrammes to the 
nearest 4 milligrammes, and very likely to the nearest 
milligramme. I mean now to make such a balance for 
ordinary use. 

What I now have and have tried for the first time 
to-day up to 150 amperes is a hecto-amperemeter. The 
current enters the movable coil by 200 of the bearing wires 
and leaves it by the other 200. It is intended for 400 
amperes, but I am pretty sure it will be quite available up 
to 500 or 600 amperes. Here are results of the first 
rough trials made this afternoon : 

New Hecto-Arnperemeter. 
Current in Amperes. Observed. Calculated from No. 3. 

(1) 50 167-4 I67-33 

(2) 100 669-2 669-33 

(3) 150 1506-0 1506-0 

The unit is 6 mgrms. Thus the weight for 100 
amperes is 4-015 grammes. 

The currents were fixed at the 50 and 100 amperes by 
a test comparison with a hecto-amperemeter of the same 
kind and same gauge for which the coefficient had been 
determined by electrolysis of copper. The previous one 
had been compared with a deka-amperemeter for currents 
of from 1 2|- to i oo amperes, and had shown agreement 
within i per cent, which, for a first attempt on two 


instruments of such very different gauges, and through so 
considerable a range of current, was fairly satisfactory. It, 
and what I know otherwise, settles that the new hecto- 
amperemeter is available for currents of from 1 2 to 600 
amperes. The instrument is going to be perfectly 
portable : no amount of knocking about it can have in 
travelling can damage the bearing ligaments. Yours 

On November 9 he sends to Lord Rayleigh a 
mathematical discovery. 

The force required to tow a boat uniformly, whether 
in a canal or in an open expanse of water (supposed 
inviscid), is zero when the velocity exceeds x/jD- This 
anticipates (49-^ years after date !) Scott Russell s discovery 
as to towage in a canal. I hope in Part III. of a set of 
articles on Stationary Waves, which I am sending to the 
Phil. Mag., to give a table of the forces required for 
towage, at different speeds, up to +//D, of a boat whose 
length is short in comparison with the wave-length 
corresponding to its speed, and comparable with, or 
much greater than, the breadth of the canal. 

About the end of 1886 there arose a rather angry 
public dispute about priority in connexion with the 
invention of the seismometers used for making auto 
matic records of earthquakes. To one of the dis 
putants, who had brought the matter to Sir William 
Thomson s notice, he wrote : 

I am very sorry if any one concerned has said any 
thing that could be personally disagreeable to any other ; 
and I cannot but think that all these questions of fact, 
so far as the public can take any interest whatever in 
them, could and should be discussed without coming within 
a hundred miles of anything acrimonious. If any 
one person has said anything acrimonious I will advise 


himself and every other person concerned to determinedly 
avoid doing the same again. 

On January 3, 1887, Sir William Thomson wrote 
from Druid s Cross, Wavertree, to Lord Rayleigh, 
telling him that he was going to give a Friday even 
ing discourse at the Royal Institution on January 
21, on the origin of the Sun s Heat. The letter 
tells of more work on the balances and their sus 
pensions, and of more articles on deep-sea waves. 
It ends with a note of politics : 

And how do you feel about Randolph ? Not dis 
tressed, I hope. I hope Mr. Goschen s acceptance will 
do good. Surely Ireland is already feeling a benefit from 
something like stability of government, with promise of 

The Royal Institution discourse on the Origin 
and Age of the Sun s Heat gave an epitome of views 
which have been stated in Chapter XIII. It appeared 
in substance in Good Words, 1887. It was an 
attempt to explain the enormous radiation of the 
sun equivalent to 78,000 horse-power for every 
square metre of his surface on Helmholtz s theory 
that the energy to maintain this output is furnished 
by a gravitational contraction of his mass. The 
lecture is a striking example of Lord Kelvin s method 
of illustrating recondite problems, such as those of 
the dynamics of a nebula, by imaginary models in 
which billiard balls or marbles are supposed to be 
flying about a room and striking against its walls 
or floor. He referred to the development of the 
mathematical theory of the gaseous nebula by 


Mr. Homer Lane, and indulged in the customary 
diatribe against the "awful and unnecessary toil and 
waste of brain-power " involved in the use of the 
British system of inches, feet, and yards. At the 
close he pictured most graphically the primitive 
formation of a gaseous nebula by the falling together 
of " twenty-nine million cold solid globes, each of 
about the same mass as the moon," and then 
sketched the possible subsequent history of such a 
nebula as it settled down into a rotating system. 

This is just the beginning postulated by Laplace for 
his nebular theory of the evolution of the solar system, 
which, founded on the natural history of the elder Her- 
schel, and completed in details by the profound dynamical 
judgment and imaginative genius of Laplace, seems con 
verted by thermodynamics into a necessary truth. 
Thus there may in reality be nothing more of mystery in 
the automatic progress of the solar system from cold 
matter diffused through space, to its present manifest 
order and beauty, lighted and warmed by its brilliant sun, 
than there is in the winding up of a clock and letting it 
go till it stops. I need scarcely say that the beginning 
and the maintenance of life on the earth is absolutely and 
infinitely beyond the range of all sound speculation in 
dynamical science. The only contribution of dynamics 
to theoretical biology is absolute negation of automatic 
commencement or automatic maintenance of life. 

In the reprint of this discourse in Vol. I. of the 
Popular Lectures, he added, at the word "clock" 
in the antepenultimate sentence, the following foot 
note : 

Even in this, and all the properties of matter which it 
involves, there is enough, and more than enough, of 
mystery to our limited understanding. A watch spring 


is much further beyond our understanding than is a gaseous 

Amongst the papers read this season was a com 
munication to the Glasgow Philosophical Society on 
a double chain of electrical measuring instruments 
to measure currents from the millionth of a milli- 
ampere to a thousand amperes, and to measure 
potentials up to forty thousand volts. To produce 
such a series of instruments demonstrates an extra 
ordinary devotion to the attainment of scientific 

On August 2nd the Institution of Mechanical 
Engineers held a Conference in Edinburgh, and 
here Sir William gave the lecture on Ship-Waves 
noticed elsewhere (see p. 748). 

The following letter is entirely characteristic in 

matter and manner : 

Aug. 6/87, 

DEAR LORD RAYLEIGH I have had a very bad 
time since your last letter came, or I should not have let 
so long time pass without writing in return. The worst 
on the whole has been, wave-making far in the rear of an 
infinite fleet of equal and similar ships moving " in line 
abreast." This has tortured me chronically since last 
December and acutely for about three weeks till two 
days ago. But I have been afflicted by a complication 
of ailments, among which turbulent motion of water 
between two planes has given me much suffering. 

I asked Stokes three questions yesterday. He 
answered each unhesitatingly. 

(i) Given an inviscid fluid moving in a pipe with the 
same laminar (steady) motion as it would have if it were 
viscous and were moving steadily under the influence of 


gravity (or a distant piston pressing it through the pipe). 
Do you think the motion of the inviscid fluid would be 
stable? Answ. No. 

(2) Do you think a needle balanced on its point 
resting on the bottom of a basin of very thick treacle 
would be stable ? Anszv. No. 

(3) Do you think viscosity of the fluid could give 
stability to the motion specified in Quest. I ? 

Answ. Yes. 

This seems to prove my case. We are tremendously 
interested in your coloured photo gv of spectrum and your 
theory of the affair. 

My wife joins in kind regards to you and Lady 
Rayleigh. I looked for you, both in the Jumna and 
Serapis, at the Review but could not see you. I have 
no message to give from Stokes as he tells me he has 
been writing. Yours truly, W. THOMSON. 

P. S. Stokes refuses to bet that a mass of water 
falling into water will develop finite slip. Yes. Vertically, 
he says no. 1 " If falling with horizontal component, motion 
requires further consideration." But he won t take 3 to I 
in half-crowns. 

August 3ist brought round the meeting of the 
British Association at Manchester, and here Sir 
William had four papers to read. Two of these 
were on his electric balances, one was on the 
turbulent motion of water flowing between two 
planes, and one on the vortex theory of the 
luminiferous ether. This was a development of 
ideas broached in the Baltimore Lectures, and bore 
a second title, phrased in the purest Kelvinese, " On 
the Propagation of Laminar Motion through a 
Turbulently Moving Inviscid Liquid." 

A long letter on stability of wave motion, to 

1 He does not admit this unqualifiedly. He says probably no. 


Lord Rayleigh, on September 26, winds up with a 
reference to the acceptance of the Irish Secretary 
ship by Mr. Arthur J. Balfour. 

I hope the Secretary is being well refreshed by 
Scotland. Very soon (a week or two more or less) I 
trust there will be an uneventfulness in Irish History that 
will sadly baffle the most ingenious and venomous of 
Gladstonites, and that may cause their great leader to 
endeavour not to remember Mitchelstown. 

On July 27, 1887, the Jubilee of the Electric 
Telegraph that is, of the first British line, from 
Euston to Camden Town was celebrated by a 
dinner in London presided over by the Postmaster- 
General, and at which Sir Charles Bright, Sir 
William Thomson, Mr. J. Brett, Mr. John Fender, 
Sir James Anderson, and others of the old cable 
and telegraph services were present. Responding 
for the toast of telegraphic science, Sir William 
Thomson referred to his comrades and associates in 
the pioneering work of 1857 to 1866, most of whom 
had passed away. He eulogized the names of 
Edward and Charles Bright, Whitehouse, Werner 
and William Siemens, Canning, Clifford, Varley, 
Jenkin, Willoughby Smith, the navigators Moriarty 
and James Anderson, and the financiers Cyrus Field 
and John Fender, whose steadfast perseverance had 
led to success. After pointing out the great im 
provements of recent date in land telegraphy he 
concluded with the words : 

I must say there is some little political importance in 
the fact that Dublin can now communicate its requests, 


its complaints, and its gratitudes to London at the rate 
of 500 words per minute. It seems to me an ample 
demonstration of the utter scientific absurdity of any 
sentimental need for a separate Parliament in Ireland. 
I should have failed in my duty in speaking for science 
if I had omitted to point out this, which seems to me a 
great contribution of science to the political welfare of the 

Much time was spent this season by Sir William 
Thomson at Netherhall, which in previous years 
had been somewhat neglected in the autumn in 
favour of the Lalla Rookh. An extract from the 
diary of his niece, Miss Agnes G. King, gives a 
picture of the family doings : 

July 2\st, 1887. Uncle William is going off to-day 
to Portsmouth to be present at the grand review of the 
fleet in honour of the Jubilee. ... I have been out all 
morning since breakfast watching the two brothers lopping 
branches from the great tree near the front of the house 
where the garden chair is placed. 

Mrs. King wrote to her daughters from 
Glasgow : 

Nov. 6, 1887. When I arrived here yesterday Uncle 
William and Aunt Fanny met me at the door, Uncle 
William armed with a vessel of soap and glycerine pre 
pared for blowing soap-bubbles, on a tray with a number of 
mathematical figures made of wire. These he dips into the 
soap mixture and a film forms or adheres to the wires very 
beautifully and perfectly regularly. With some scientific 
end in view he is studying these films. I was at once 
taken into the study to see them, and while Uncle William 
was showing them to me and giving me such explanations 
as I could take in, he was teaching Dr. Redtail to whistle 
" Merrily danced the quaker s wife " Dr. Redtail being 
in the dining-room, and the teacher and pupil carrying on 


the lesson at the top of their voices. The whole evening 
was occupied with the soap mixture, the wire figures, and 
the tobacco pipe, while Aunt Fanny read aloud Mr. 
Balfour s speech. 

On Friday afternoon five big stones were thrown 
through the study window and four panes of plate glass 
smashed as well as the fern case. It turned out to be 
the deed of a maniac who gave as a reason for the 
mischief he had done that Sir William was a villain who 
had rained electricity on his head. He has been sent to 
an asylum. 

Nov. 13, 1887. Yesterday Uncle William was at 
Dundee on business. When Aunt Fanny and I sat 
down to table, and Dr. Redtail perceived Uncle William s 
place vacant, he immediately shouted out, " Where is Sir 

Nov. 15, 1887. The excitement about the election 
became very wild, procession after procession of reds (for 
Lord Rosebery) and blues (for Lord Lytton) headed by a 
couple of pipers in kilts marched round the courts, and, as 
they passed the house, halted to hurrah for Sir William. 

The next letter is an echo of an unsolved diffi 
culty met with in the Baltimore Lectures (p. 819). 

Nov. 20/87. 

DEAR LORD RAYLEIGH 1 am afraid I am a month 
already your debtor for your last letter. I had a bad 
time (at the beginning of which I hoped I might have 
seen you in London) after receiving it and tried hard to 
make out an unexceptionable proof of stability, but with 
out success. I quite see the force of your objection, and 
admire the mathematical theory of various wonderful 
Maskelyne and Cooke performances which it suggests. It 
certainly vitiates my seeming proof of stability ; but 
still I think it might be explained away and my proof 
completed. This kind of seeming test for stability does 
not detect (as you show it does not) the instability of a 


system disturbed from a position of static equilibrium. 
But it does detect instability (as I maintain and I think 
you will admit) in the parabolic laminar motion of an 
inviscid fluid, and it proves that viscosity annuls this 
kind of instability, but I cannot maintain that it proves 
stability. There can be no peace or happiness in this 
position of affairs, so you may think of me as very 
miserable ; but I have become involved in another affair 
(see Phil. Mag. Dec., or enclosed scrap) which George 
Darwin characterizes as utterly frothy ; and having 
launched it the waves in crystals have come on with 
very interesting, almost happy result. I find that if a 
homogeneous, isotropic, elastic solid (suppose for the 
moment it be incompressible) be drawn out with 
different forces in different directions ; so that with 
reference to O;tr, Oj>, Qz fixed relatively to the solid, and 
remaining at right angles to one another, the co-ordinates 
xyz of a point in the solid when unstrained, become 
ctx y fiy, <yz when strained (at/3y = 8). . . . The velocities 
are the same for the same directions of vib n- , and we have, 
as shown by Green, Fresnel s wave-surface. But the 
condition (i) is absolutely natural and simple; being 
essentially true for infinitesimal values of a i, j3 I, 
7 i , and certainly true approximately, very approximately^ 
perhaps approximately enough to jit our knowledge if not 
also your result for such values as would correspond 
to Iceland Spar (? is it the most doubly refractive of all 
crystals) : and certainly very approximately (not so far 
as I can yet see rigorously, rather probably not) for 
foam pulled unequally in different directions. This is a 
great contrast to " Green s Second theory," and Stokes s 
report on it. Stokes felt the assumption needed to bring 
out Fresnel s wave-surface so strained that the whole 
thing was unacceptable. It involved an independent 
aeolotropy of the solid, which it modified into fitness for 
Fresnel, by a precise adaptation seemingly unconnected. 
I always felt Green s dynamical preliminary investiga 
tion unintelligible (indigestible as I see I called it at 
Baltimore), and it is really quite wrong in its seeming 


result, which would give laminar wave propagation in a 
fluid by EQUAL negative (although not said to be negative) 
in all directions. Still one cannot but feel that Green 
had really divined the secret, and wanted only to write it 
out better (by aid of T and T r ) ! to make it perfect. 

What I have made out just now (since coming here 
yesterday this is the best place for produce I always find) 
is, I think, really interesting and important : particularly 
as showing all we want, and no possibility of anything 
else, produced by unequal pull in different directions 
on an isotropic solid (Force will do it all) instead of 
having 18 moduluses to whittle down to two. Nothing 
I can yet see, however, diminishes the difficulty of the 
polarization by reflexion. 

Have you been getting good results in weighing, 
etc. etc. ? 

I hope you and Lady Rayleigh have been well, and have 
still a good report to give from Ireland. Mr. Gladstone 
seems rather frightened that he has gone too far in urging 
maltreatment of the police, and I think we may fairly 
hope that the tide has turned. My wife joins in kind 
regards. Yours always truly, W. THOMSON. 

A communication to the Royal Society of 
Edinburgh on December 8, on Cauchy s and Green s 
doctrine of extraneous forces, was the outcome of 
the ideas revealed in the above letter. 

About this time the possible arrangements of 
molecules in crystalline and other solids began to 
claim Sir William Thomson s attention, and his 
" green books " for three or four years abound in 
pages of notes and calculations on the packing of 
molecules in different arrangements, and in the 
partitioning of space by assemblages of primitive 
particles of different shapes grouped so as to make 
homogeneous solids. Many physicists had tried 



their hands at different kinds of grouping. Piles of 
cannon-balls, groups of cubes, assemblages of six- 
sided cells like a honeycomb, and many others had 
been suggested as models of molecular grouping ; and 
many such are to be found sketched in the note 
books with calculations about the elastic and other 
properties of such structures, including piles of 
equal bubbles assembled as foam. One form to 
which Sir William gave great attention was that 
known as the tetrakaidekahedron the solid with 
fourteen faces which may be looked upon as a 
transition form between the cube and the octahedron, 
and which he came to regard as a fundamental form 
as constituent of a homogeneous grouping. It will 
be seen later how, by models of various groupings 
of molecules, he sought to elucidate the problem of 
the ultimate structure of matter. 

The collection of his scattered mathematical and 
physical papers and their revision for reprinting 
proved a lengthy process. Vol. I. had been finished 
in July 1882, and Vol. II. in November 1884; but 
Vol. III. still dragged on. In February 1888, Sir 
William was reported to be deep in a last new article 
to finish the volume. This work he interrupted, 
however, to give to the Geological Society of 
Glasgow a lecture, on February 16, on Polar Ice- 
Caps and their influence in changing Sea- Levels. 
The main point in this paper was the influence of 
the ice-cap of the Antarctic continent on the sea- 
level and climate of the globe. Croll had estimated 
the thickness of the Antarctic ice as 1 2\ miles. From 


experiments on the plasticity of ice, and the 
estimated area of the Antarctic continent, Sir William 
reckoned it to be three miles thick. If, owing to 
slow astronomical changes, the average annual snow 
fall at the Antarctic were to be increased, the result 
after a few hundreds of years would be, to increase 
the cap, lower the level of the sea all over the globe, 
diminish oceanic circulation, and tend also to cool 
the Arctic ocean, increasing the amount of glaciation 
in the northern hemisphere simultaneously. The 
ocean is the great carrier of heat ; the most potent 
influence for altering the climate in any part of the 

The following extract from a letter to a corre 
spondent gives a contemporary view on the question 
of electric lighting, then beginning to be widely 

adopted : 

28M Feby. 1888. 

... As to the Electric Light ; I quite expect that it 
will altogether supersede gas lighting in cities, although 
it is impossible to say how soon. If it were at present 
supplied to houses at twice the price of gas, the light bill 
would be less in most private houses than at present, 
because the electric light can be extinguished in an instant 
in any place where it is not wanted, and relighted in an 
instant, with the greatest possible ease. The storage of 
electricity is too costly for very general use, but it is 
quite unnecessary in any very large-scale electric lighting. 

On February 9 he wrote Lord Rayleigh that he 
was trying hard to find "a convenient and useful 
hydrokinetic analogue for electromagnetic induc 
tion," which was wanted to complete Vol. III. of 
the Collected Papers, the last sheet of which was 


waiting for it half finished. He wrote again on 
March 2 : 

I am in great agony to get out Vol. III. of my 
Papers. It has hung fire 5 or 6 weeks, with the last 
sheet half printed and waiting for a hydrokinetic analogy 
for electromagnetic induction (a very trumpery affair 
I am afraid you will think it not even including soft 
iron, but still somewhat useful). I hope to get it done 
in a few days, but I have been much disturbed with 
the delay and difficulty of getting time to fix up the 
affair. Lady Thomson bids me say " we hope that 
Mr. Balfour is keeping well, because we think the whole 
nation depends on it"; and I say so most decidedly. We 
had great excitement and joy over Deptford. 

In April he wrote : "I am still in the agony of 
getting my Vol. III. finished." 

On May 3 he lectured on Waves to the Cork 
Literary and Philosophical Society. 

The diary of Miss Agnes G. King tells of doings- 
at Netherhall. 

July 28, 1888. 

Uncle W. and Aunt F. arrived about eight, bringing 
M. du Bois (a gentleman from Holland) with them. 
During dinner and in the evening Uncle W. talked with 
great animation to M. du Bois, drawing from him all 
possible information about his kind of work in the 
laboratory in Strasburg, also about public feeling in that 
part of Germany with regard to the late and present 
emperors. He also drew out all he could about the 
social state of Holland, political and private, and its 
relation to Belgium. At ten he asked me to play the 
piano, and immediately his whole attention was given 
to the music, detecting the composer by the difference in 
style and quite surprised if he made a mistake. The 
moment a few chords of Der Freischutz were struck he 
got quite excited, and rising from his chair he came and 


stood behind me not to lose a single note. " There is 
nothing," he said, " more beautiful than Der Freischutz ; 
there is stuff in it for at least four operas. Weber is a 
most original and perfect composer." Bits in which he 
used to take part long ago with his horn gave him 
special delight. . . . 

It was wet in the afternoon, but in spite of the rain 
Uncle William, Aunt Fanny, M. du Bois and I went out 
for a scramble. First we scrambled up to the loft to see 
the carrier pigeons, and Uncle W. asked the coachman 
many questions as to why the various pigeons were 
separated from one another. In the evening I played 
again to Uncle William. 

. . . After breakfast Uncle W. stood for a while with 
a delighted expression gazing at the reflexion of the 
window in the polished oak table in the turret window, 
nodding his head from side to side. " Come all of you 
quick and look ! I see Heidinger s brushes better than 
I ever saw them before." We all came and Aunt Fanny 
was able to discover them for the first time, but I do not 
think any of the rest of us saw them at all. Uncle W. 
told us how he had given a lecture on them one evening 
on board a ship going to America, and next morning it 
was very funny to see all the people nodding their heads 
from side to side and gazing intently at the clouds. 

When sending to Lord Rayleigh, on August 25, 
a piece of Iceland-spar showing striations due to 
artificial twinning, he added a political postscript : 

Did you not remember the political prisoners chained 
to the most atrocious felons in Naples thirty-seven years 
ago ? I should think Mr. Gladstone is the only person of 
over forty-three in the United Kingdom who does not. 
But if he had forgotten the state of things in Naples 
thirty-seven years ago, he should have made himself 
acquainted with it again, before comparing the regimes 
of the two B s, as he did to the ignorant potters last week 
at Hawarden. 


September 5th brought the meeting of the British 
Association at Bath. At the Mathematical and 
Physical Section, under the presidency of Fitz- 
Gerald, there were notable discussions. Sir William 
contributed three papers, and joined in a fourth 
along with his former pupils, Professors Ayrton and 
Perry, concerning a new determination of "v" 
the ratio of the electromagnetic and electrostatic 
units. His papers were : A Simple Hypothesis for 
Electromagnetic Induction of Incomplete Circuits ; 
On the Transference of Electricity within a Homo 
geneous Solid Conductor ; and On Five Applica 
tions of Fourier s Law of Diffusion, illustrated by 
a diagram of curves with absolute numerical values. 
This last, reprinted in Vol. III. of the Mathematical 
and Physical Papers, p. 428, was a discussion of 
the equation which Fourier had found for the 
"linear motion of heat," as now applied to other 
physical "qualities"; the velocity of motion as 
propagated into a viscous fluid ; the diffusion of 
liquids into one another ; the diffusion of induced 
electric currents into a homogeneous conductor 
(which Heaviside had shown to be analogous to 
the setting of water into motion by friction on its 
boundary) ; and the diffusion of electric potential in 
the conductor of a submarine cable. This short 
but useful paper was strongly reminiscent of the 
article on the " Uniform Motion of Heat," which 
Thomson had given forty-six years before (see 
p. 42) when an undergraduate. The other two 
papers belong to the burning question of 1888, 


electromagnetic theory. Sir William, as we know, 
had never accepted Clerk Maxwell s electro 
magnetic theory of light, nor the notion of " dis 
placement currents," on which that theory is based. 
His reasons for this attitude are discussed on pp. 
1021-1025 below. But in the recent years Maxwell s 
pupils and disciples, Lord Rayleigh, FitzGerald, 
J. J. Thomson, Hopkinson, Glazebrook, Poynting, 
O. Heaviside, Oliver Lodge, and others, had been 
actively pushing Maxwell s theory and testing its 
applications. Lodge, in particular, had studied the 
phenomena of the propagation of electric waves 
along wires, with many beautiful experimental 
illustrations of their reflexion, and the establish 
ment of nodal points, when periodic surgings were 
reflected. For two years, indeed, the application 
of these considerations to lightning protection had 
engaged the British Association. But now, on the 
top of all this, came the splendid work of Hertz, 
proving experimentally that electric waves, gene 
rated by the sudden discharge of charged con 
ductors, as suggested by FitzGerald in 1883, could 
be propagated across open space without wires, 
reflected and refracted, just as waves of light can 
be, and herein obeyed Maxwell s equations. 

Sir William s part in this discussion is recounted 
on p. 1041 infra. 

To the Philosophical Magazine of November 
1888, Sir William contributed a striking paper, 
which has not been reprinted elsewhere, " On the 
Reflexion and Refraction of Light." 


Litigation about the compass (see p. 718) kept 
Sir William Thomson in London for more than a 
week in the autumn of 1888, and he stayed with 
his widowed sister, Mrs. King, then residing in 
Hamilton Terrace, St. John s Wood. The diary 
of Miss Agnes G. King records some of the events 
of the time in the following extracts : 

Nov. 20, 1888. Case of Infringement of Compass 
came on at last ; should have begun on Friday. Uncle 
William and mother dined at Sir Antony Hoskins s. Sir 
A. said to mother, " I cannot tell you how all we naval 
men love your brother." Mother answered, " I think 
everybody who knows him likes him." " Likes him ! " 
said Sir A. " Like is not the word ; we all love him." 

Nov. 21, 1888. We had great excitement at breakfast 
dressing up eggs boiled and raw in little net bags, and 
suspending them by threads, to demonstrate the steadying 
effect of the oil under the compass box. The arrangement 
was quite a success, and Uncle W. went off in delight 
with his new toy, intending to call on Sir A. Hoskins on 
his way to Court and show it. ... Uncle W. came home 
in the evening looking very bright ; everything had gone 
well, and the warm and hearty evidence which his friends 
among the naval men had given, pleased him exceedingly. 
Captain Fisher s evidence was specially strong and very 
amusing from all accounts. He described the absolute 
steadiness of the compass in the bombardment of Alex 
andria, when great guns were going off under it and 
beside it. 

On his return to Glasgow he wrote, on 
November 27, to Miss Agnes G. King : 

Tell your mother that I look back with great pleasure 
to my time in Hamilton Terrace last week and the week 
before. It brightened for me a very anxious and irksome 
duty in London, the latter part of which, however, became 



a pleasure, thanks to Captain Fisher and the other naval 
and nautical men who gave much pleasing and amusing 
evidence, and to the happy conclusion of the case. 

Sir William s insatiable curiosity to know the 
latest data of science is illustrated by the following 
postcard written to Professor Ewing, in the train, 
on December 21, 1888, on his way to Knowsley, 
for the usual Christmas visit to Lord Derby : 

What is the very greatest magnetic force in air that you 
have got ? I suppose no one in the world has got 
greater. What is your very greatest intensity of magneti 
zation ? Wishing you a happy Xmas and " good New 

In 1888 the Society of Telegraph Engineers 
was reconstituted on a wider basis as the Institution 
of Electrical Engineers, and Sir William Thomson 
was invited to assume the Presidency of the Insti 
tution for the year 1889. On January 10 Lady 
Thomson wrote to George Darwin : 

Sir William has been very busy over his inaugural 
address as President of Electrical Engineers, which he 
gives to-morrow night. He goes to London to-night 
and returns here Friday, by day or night. 

The main part of this address 1 was devoted to 
the subject of Ether, Electricity, and Ponderable 
Matter, and the relations between them. It was 
prefaced, however, by allusions to the addresses 
of some of the former Presidents of the Society, 
and with a little note as to personal history. He 
had spoken of the perplexity caused to early 

1 Journal of Institution of Electrical Engineers, xiii., 1890, pp. 4-37 ; 
reprinted in Mathematical and Physical Papers, vol. iii. pp. 484-515. 


workers in submarine telegraphy by the inductive 
embarrassment met with in cable-signalling, and of 
Faraday s prediction that the Leyden-jar-like action 
of the gutta-percha coating would cause retardation, 
and of Varley s further investigation of 1854. 

And then came on the great Atlantic cable question. 
I always remember how that question came upon me. I 
see in Professor Stokes s presence with us this evening a 
reminder of the circumstances. I was hurriedly leaving 
the meeting of the British Association [Liverpool, 1854], 
when a son of Sir William Hamilton, of Dublin, was 
introduced to me with an electrical question. I was 
obliged to run away to get to a steamer by which I was 
bound to leave for Glasgow, and I introduced him to 
Professor Stokes, who took up the question with a power 
which is inevitable when a scientific question is submitted 
to him. He wrote to me on the subject soon after that 
time, and some correspondence between us passed, the 
result of which was that a little mathematical theory was 
worked out, 1 which constituted, in fact, the basis of the 
theory of the working of the submarine cable. In that 
theory electromagnetic induction was not taken into 
account at all. The leaving it out of account was justi 
fied by the speed of signalling which the circumstances of 
a cable exceeding 200 or 300 miles in length dictated. 

Sir William then went on to say how this further 
question of electromagnetic induction the retarda 
tion due to the magnetic field created around the 
conductor by the current itself had been investi 
gated by him, and found to be absolutely imper 
ceptible at the highest speed suitable for working 
the cables then proposed. But now that old 
question was being revived. 

1 By Thomson himself, see p. 331 ante. 


I had myself laid it aside in some corner of my mind 
and in some slight corners of my notebooks for forty 
years. Within the last forty days I have really worked 
it out to the uttermost, merely for my own satisfaction. 
But in the meantime it had been worked out in a very 
complete manner by Mr. Oliver Heaviside, who has pointed 
out and accentuated this result of his mathematical theory 
that electromagnetic induction is a positive benefit : it 
helps to carry the current. It is the same kind of benefit 
that mass is to a body shoved along against a viscous 

This is at once followed by a highly characteristic 
passage, in which Sir William illustrated the result 
of mathematical theory by imagining a dynamical 
model, in this case a carriage supposed to be 
travelling through a viscous fluid : 

Take a boat not floated but partially supported on 
wheels, so that when loaded more heavily it will not sink 
deeper in the fluid. . . . We will shove off two boats with 
a certain velocity the boats of the same shape ; but let 
one of them be ten times the mass of the other : it will 
take greater force to give it its impulse, but it will go 
farther. That is Mr. Heaviside s doctrine about electro 
magnetic induction. It requires more electric force to 
produce a certain amount of current, but the current goes 
farther. . . . Old telegraphists remember that they always 
used to say three or four good leaks in a cable, if they 
would but kindly remain constant, and not introduce 
extra trouble by earth currents, would make the signalling 
more distinct. . . . Heaviside s way of looking at the 
submarine cable problem is just one instance of how the 
highest mathematical power of working and of judging as 
to physical applications helps on the doctrine, and directs 
it into a practical channel. 

He then added "one little piece of practical 
information," in the shape of a formula for the 


ratio which represents the increase in the resistance 
of a copper wire, when used for rapidly alternating 
currents, arising from differences in the current- 
density at the axis and at the periphery of the wire. 
The formula was in terms of Bessel functions (real 
and imaginary), and was accompanied by a numerical 
table of values worked out. He then turned to the 
hydrokinetic analogies by which he had been 
endeavouring to elucidate electromagnetic theory. 
It was, he said, merely a mathematical working 
analogy, and as such exceedingly useful and 
instructive, and a very potent one in helping us 
in guessing out and in thinking out the practical 
problems of electromagnetic induction. But there 
was another analogy to which he gave the prefer 
ence the elastic solid idea which he had broached 
in 1846 (see p. 198), only twenty-eight days after 
he had entered on the work of his professorship. 
He had then attempted to represent electric forces 
by the displacement, and magnetic forces by the 
resultant rotations of an elastic body ; and had then 
declared that a special examination of the states 
of a solid body, representing various problems in 
electricity, magnetism, and galvanism, must be 
reserved for a future paper. 

As to this last sentence, I can say now what I said 
forty-two years ago "must be reserved for a future 
paper " \ I may add that I have been considering the 
subject for forty-two years night and day for forty-two 
years. I do not mean all of every day and all of every 
night ; I do not mean some of each day and some of each 
night ; but the subject has been on my mind all these 


years. I have been trying many days and many nights 
to find an explanation, but have not found it. 

If we had nothing but electricity and ether to 
consider, the problems of the electromagnetic 
analogy could be realized by a model of an elastic 
solid body having tubular pores filled with a dense 
viscous fluid. But there was also magnetism to be 
accounted for ; and he asked the audience to consider 
the case of a solenoid having an electric current 
circulating around its coils. "Whatever the current 
of electricity may be, I believe this is a reality : it 
does pull the ether round within the solenoid." And 
yet though the ether could thus be pulled, as if it 
were an elastic solid, the earth moves through it. 
This led him to discuss the idea of an incom 
pressible medium which yet possessed elasticity, 
and to suggest a sort of imaginary model of a web- 
like structure in which the rigidity was given to the 
medium by putting a gyrostat into each element of 
the structure. But now, although such a medium 
would afford a dynamical explanation of magnetism, 
it left out unexplained the electrostatic forces. And 
so the end was not satisfying. 

And here, I am afraid, I must end by saying that the 
difficulties are so great in the way of forming anything 
like a comprehensive theory, that we cannot even imagine 
a finger-post pointing a way that can lead us towards the 
explanation. I only say we cannot now imagine it. But 
this time next year this time ten years this time one 
hundred years probably it will be just as easy as we 
think it is to understand that glass of water, which now 
seems so plain and simple. I cannot doubt but that 


these things, which now seem to us so mysterious, will be 
no mysteries at all ; that the scales will fall from our eyes ; 
that we shall learn to look on things in a different way 
when that which is now a difficulty will be the only common- 
sense and intelligible way of looking at the subject. 

On several occasions during this session of his 
Presidency, Sir William Thomson took part in the 
discussions at the Institution of Electrical Engineers ; 
amongst the papers discussed being those of Dr. 
(now Sir) Oliver Lodge on Lightning and Lightning 
Protectors ; of Mr. W. M. Mordey on Alternate 
Current Working ; of Mr. G. Hookham on Electric 
Current Meters. 

He lectured in the spring of 1889 at the Royal 
Institution on Electrostatic Measurement; he also 
delighted the Belfast Natural History Society with 
an exhibition of gyrostatic experiments. In May 
he was busy thinking about systems of mutually 
repelling particles and groups of molecules. All 
this work issued in an important paper read to the 
Royal Society of Edinburgh, on July i, on the 
Molecular Constitution of Matter (see p. 1050 infra]. 

In view of the approaching Electrical Congress 
in Paris, M. Mascart wrote to Sir William Thom 
son, inviting him to be present. Sir William s reply 

was negative. 

June 4, 1889. 

DEAR MR. MASCART Your most kind letter has 
been forwarded to me here. Alas, alas, I cannot have 
the pleasure of being in Paris to take part in the Congress 
of Electricians in August and to see the great Exhibition. 
I have been kept very much in London by my duties as 


President of the Institution of Electrical Engineers, and I 
shall be detained still till near the end of the present 
month, with official business and duty, connected with the 
establishment of an electrical standardizing laboratory, 
which we hope is to be taken in hand by our Government. 
After so long an absence, I must return to Scotland and 
remain there steadily to get through arrears of work 
which have been of necessity accumulating all this time. 

Lady Thomson and I have enjoyed all our visits to 
Paris so much, and particularly the last one, that we shall 
certainly go again when we can ; and we look forward as 
a pleasure to come, to see you, and Mr. Bertrand, and your 
families in your homes, as we saw you all this time last 
year, and again to attend a meeting of the Academy and 
see our colleagues there. 

But in the meantime will you and Madame Mascart 
not come to Scotland after your labours in the Congress 
are over, and take a little holiday, for which by that time 
you will, I am sure, be quite ready ? Scotland is still very 
good in September, and it would be a great pleasure to us 
to have a visit from you in our country house, Netherhall, 
about 30 miles from Glasgow. We can run up by rail 
with great ease any day to my laboratory, which is always 
open, all the year round, if you would care to look in to it 
for an hour and see what we may have in hand. 

My wife joins in kindest regards to you and your 
family and I remain, yours always truly, 


Mascart, however, wrote again, urging him to 

come, and he consented. 

June 23, 1889. 

DEAR MR. MASCART I cannot resist your letter of 
the i 8th, kindly insisting on my presence at the Congress 
of Electricians, and I have therefore arranged to come to 
Paris in time to attend at the opening meeting on the 24th 
of August, and to remain for, at all events, several days. 

Lady Thomson will be with me, and looks forward 


with pleasure to seeing you and Mme. Mascart again in 
Paris, since you will not come to see us here this year. 
Believe me, yours very truly, WILLIAM THOMSON. 

The next day he wrote to Lord Rayleigh. 

I am going to Paris after all to be present at the 
opening of the Electrical Congress on the 2 4th of August,, 
and to remain a few days of it. I had such an appeal 
ing letter from Prof. Mascart that I could not resist ! 
I wish you were coming too. Will you not come? It 
would be much better fun with you. ... I found on our 
way from London to Glasgow last Thursday a complete 
settlement of the Boscovich theory of elastic solid. A 
homogeneous system of single points in equilateral 
tetrahedral order, each attracting or repelling its next 
neighbour, according as the distance between them is 
greater than, or is less than, a (the edge of the static 
tetrahedron) gives a stable elastic solid. . . . 

On August 5 he wrote again to Lord Rayleigh 
on the subject of surface - tension, and makes a 
reference to the capillary curves given in Vol. I. of 
his Popular Lectures. 

Before I knew of Neumann s having done anything 
in the matter 1 saw his theorem in soup (every time I 
had it) of a particular kind. The pictures, p. 27 of my 
" Pop " (by the bye this title has been abused un 
mercifully by Critics in the newspapers), were drawn 
from observation. 

In August came the Electrical Congress in Paris. 
Sir William took the opportunity to make three 
short communications to the Academic des Sciences, 
one on the molecular tactics involved in the 
artificial twinning of Iceland : spar ; another on the 
equilibrium of atoms and on the elasticity of solids 
in the theory of Boscovich ; the third being a 


description of one of his models to visualize the 
physical properties of the ether. Sir William and 
Lady Thomson returned from Paris on September 4. 
On the iith they were at Newcastle attending 
the British Association meeting, to which he gave 
a paper on Boscovich s Theory. After the meeting 
they stayed on, during which they were the guests 
of Captain (now Sir Andrew) Noble, for a few days 
with Lord Armstrong at Cragside. In November 
came the news that Sir William had been made a 
Grand Officer of the Legion of Honour. 

Mrs. King, staying in her brother s house at 
the University in November, sent letters to her 
daughters which afford glimpses of his activities 
and engagements. 

Nov. 22, 1889. . . . Uncle William went to London 
last night. He dined comfortably at 7.30 on all the 
courses, including entrees and game and his coffee, and set 
off in good, quiet style, and the ladies went up to the 
drawing-room when, lo and behold ! there was the " green 
book " lying on the sofa. The telephone was instantly 
in requisition to summon a cab with all speed, and 
Margaret the housemaid was ordered to meet it, and being 
a capable woman she did so and succeeded in putting the 
precious book into Uncle William s hands before the train 
started, and he got it before he had missed it. 

Nov. 23, 1889. Uncle William came back this morn 
ing quite fresh after his busy day in London. It was to 
meet with the Lords of the Admiralty that he went It 
is marvellous how easily travelling is conducted now. He 
goes so often by night to London the railway attendant 
knows exactly how to make his bed, and all the little 
arrangements he likes, and attends most carefully to his 
comfort. He drove at once to Admiral Fisher s, where 
he had his bath before 8.30 breakfast, and then set off 



about his various business. The meeting with the 
Admiralty was most satisfactory to him, for it is now 
ordained that his be the standard compass, and be used 
throughout the Navy. 

Much mean and underhand work has been brought to 
light. For instance, of 60 letters (I suppose in answer 
to inquiries) from Captains, one from the Captain of the 
Euryalus spoke of some slight objection to the compass, 
eight said they had not had sufficient experience, and 
the remainder spoke of it in terms of unbounded 
admiration and appreciation. Of these letters the 51 had 
never been produced, but were hidden away in pigeon 
holes in the Hydrographic Office, and the disapproving 
one was made a great deal of. I believe this has been 
going on for years and that Admiral Fisher has been 
instrumental in exposing the abuse. . . . There is much 
of the Circumlocution Office in the whole affair. 
Uncle William does not want it talked of. . 

In December 1889 there was held in the Bute 
Hall of the University of Glasgow a great bazaar 
in aid of the funds of the Students Union. Sir 
William and Lady Thomson took a very active 
part in this affair, which resulted in a profit of over 
^"11,000. Lady Thomson s stall alone took over 

In this year Sir William was a member of the 
Royal Commission upon the University of London, 
which up to that time had been merely an Examining 
Body. For some years an agitation had been pro 
ceeding to create a teaching University in London. 
The majority of the Commission declared in favour 
of reconstructing the existing University. Sir 
William Thomson, along with Sir George Stokes 
and the Head Master of Harrow, presented a 


minority report, favouring the creation of a separate 
Teaching University. 

His year of presidency of the Electrical Engineers 
having expired, Sir William Thomson, on January 9, 
1900, duly installed Dr. John Hopkinson as his 
successor. Before retiring from the Presidential 
Chair, he called the attention of members to the 
fact that electrical engineering originated with tele 
graphy, and specially with submarine telegraphy. 
He reminded them that he himself had been a 
shareholder in the first Atlantic cable of 1858, 
and a co-director with Sir John Fender, who in 
the hour of crisis gave a guarantee of a quarter of 
a million sterling for the funds required for the 

On February i he wrote to Lord Rayleigh : 

Feb. i/ go. 

DEAR LORD RAYLEIGH See Maxwell, vol. ii. 537. 
Is the last paragraph of this very approximately true 
in practical cases ? 

And] have you evidence that on suddenly breaking a 
primary circuit, the total quantity flowing through a 
secondary circuit (with galvanometer coil in it) is 
independent of the suddenness with which the primary 
circuit is broken ; and that it is that calculated from the 
self-induction of the secondary circuit and the ohmic 
resistance of the secondary circuit supposing the current 
to be running full bore through it ? 

It seems to me that ordinary practical suddenness of 
breaking a primary circuit must be such that the ohmic 
effective resistance in the secondary, even if of wire I cm. 
diam., or less, must be largely augmented in virtue of the 
current not running full-bore through it during a sufficient 


part of the whole time of the discharge to consume a 
large proportion of the whole energy. I suppose I 
might find an answer to this by reading through all your 
papers and all Oliver Heaviside s, but I prefer this 
method as a shorter cut. I hope you are long ago quite 
out of the " grippe." Yours, W. THOMSON. 

This inquiry was the basis of a paper in the 
Philosophical Magazine in March 1890. 

Three days later he wrote again, on Oscillations 
of the Atmosphere, suggesting that the large semi 
diurnal term in the variations of the barometer may 
be due to one of the modes of free vibration of 
the atmosphere being in period not very different 
from twelve hours. The next letter is to von 


Feb. 24, 1890. 

DEAR HELMHOLTZ I have just this morning heard 
from Tait that the Senate of Edinburgh University has 
invited you to be Gifford Lecturer for the next period of 
two years, and I lose not a minute in writing to beg you 
to accept. We have so long wished to see you again in 
Scotland, that now, with such an occasion as this, we hope 
very much that you will be induced to come. During 
the month of the engagement in Edinburgh each year 
you must live part of the time with us in Glasgow, as the 
railway journey is quite short (i|- hour). The actual 
lecturing would, I am sure, be interesting to yourself if 
you feel that you can undertake it, which I hope will be 
the case ; and I need not say that it will be greatly 
appreciated in Scotland, and by a far wider public than 
those who will hear you, or than Scotland. 

Lady Thomson and I are here from Friday to 
Monday, as we are as often as we can get away 
from Glasgow at the end of the week, but Glasgow is our 
home during the winter session. 


It chances that Prof, and Mrs. Max Muller are 
with us and I have told him of the wish of Edinburgh. 
He allows me to say that he is most anxious that you 
should accept. He will write and tell you about the 
conditions. We hope that Mrs. von Helmholtz will come 
with you. My wife joins in urging that you should 
accept, and in kind regards to you both, believe me, 
yours always truly, W. THOMSON. 

To the Edinburgh Mathematical Society in 
February he sent a paper on the Moduluses of 
Elasticity in an Ideal Elastic Solid, constructed 
according to Boscovich s theory of an assemblage 
of points ; and in March, another on a Mechanism 
for the Constitution of the Ether, to the Royal 
Society of Edinburgh. 

In April and May he was discussing electric 
oscillations at the Glasgow Philosophical Society 
and at the Institution of Electrical Engineers. 

The remarkable discovery by Hopkinson of a 
nickel steel which could assume either a highly- 
magnetic or a non - magnetic state, according to 
treatment, excited him greatly, and on receiving a 

sample he wrote : 

March 27/90. 

DEAR HOPKINSON I shall be glad to do anything I 
can in respect to your law case should it go on and my 
assistance be desired. 

I have not hitherto been able to make any experiments 
on the specimen of nickel iron wire which you sent me ; 
but I had just within the last three or four days been 
arranging to take it in hand. So I hope very soon to 
see for myself, and to let my laboratory corps see 
something of your wonderful result. Yours very truly, 



[P. S.] I shall be very glad to hear what you find with 
the new samples. 

Sir William was still busy gathering up the 
threads to complete his third volume of Collected 
Papers, and at last, in May 1890, he was able to fix 
on a mechanical representation of magnetic force, 
which had baffled him ever since November 1846. 
The account of it constitutes Article xcix. of 
Vol. III., which he was now able to finish. Its 
preface is dated from Peterhouse Lodge, June 2, 

A project for utilizing the powers of Niagara was 
now on foot, and the American promoters turned 
for advice to the highest authorities in Europe. 
They first approached Sir William Thomson ; 
and the following letter which he wrote to Mascart 
shows the stage at which the proposition had 

arrived : 

June 2 1 /9o. 

DEAR PROF. MASCART I have to-day given a note 
of introduction to Mr. Edward D. Adams (President of 
the New York Cataract Company, controlling the Niagara 
Falls) which he will probably present you in Paris about 
ten days hence. He will be accompanied by Dr. Sellers, 
of Philadelphia, who is consulting engineer to the 
Company. They have come to Europe for the purpose 
of seeing and learning about electrical and hydraulic 
works. The Company is on a very solid foundation, 
being connected with some of the American bankers of 
highest character, and supported by all the money they 
require, so that they are not asking for subscriptions either 
in this country or in America. 

They wish to form a consulting Commission of four. 


and have asked me to preside. They wish to have you 
as one of the four, and they will explain the conditions 
and terms to you when they see you. Dr. Sellers is to 
be one of the Commission, and for the fourth they think 
of asking Mr. Turrettini (I am not sure if I spell his name 
correctly), who has done great hydraulic work at Geneva. 

I have consented to act on the Commission for them, 
and I hope you will see your way to join it also. The 
work and plans which will be put before us will be most 
interesting ; and the Company is of such a character that 
it will be thoroughly satisfactory and creditable to us 
to be associated with it as advisers. 

Lady Thomson joins in kindest regards to you and 
Madame Mascart, and reminds her of her promise to 
bring you to see us in Glasgow and Netherhall soon. 
Believe me, yours very truly, WILLIAM THOMSON. 

The Niagara Commission l of experts, as finally 
constituted, consisted of Sir William Thomson 
(chairman), M. Mascart, Col. Turrettini, Professor 
W. C. Unwin, and Dr. Coleman Sellers. Professor 
George Forbes was appointed as the official 
engineer. The promoters invited projects from the 
chief European electrical contractors, as well as 
from American engineers. Twenty - six different 
plans were submitted. After many months the 
Commissioners were in a position to report ; and 
eventually none of the plans proposed was adopted, 
though some use was made of fourteen of them. 
The engineer, in conjunction with Dr. Coleman 
Sellers, drew up the designs for the Cataract Com 
pany, and the contracts were given to American 
engineers to execute. Sir William Thomson was 

1 See Gassier s Magazine, June 1892 and July 1895 a ^ so Electrical 
Review^ Feb. 9, 1894. 


throughout and to the last entirely opposed 1 to the 
use of alternating currents in any shape, but was 
in a hopeless minority. The machines for the first 
power-house were two -phase alternators, of about 
3500 kilowatts each, and of a special type designed 
by George Forbes, having an internal fixed arma 
ture and an external revolving field-magnet system. 

In September 1890 the British Association met 
at Leeds. Sir William Thomson made five com 
munications to the sectional meetings ; on Con 
tact Electricity, on Alternating Currents in Parallel 
Conductors, on Anti-effective Copper in Parallel Con 
ductors, on a Method of Determining the Magnetic 
Susceptibility of Diamagnetic and Feebly Magnetic 
Substances, and on some of his newer electrical 

Sir William had purposed to go in October to 
Cambridge to attend the statutory meeting of the 
Fellows of his College, but for once he was absent. 
Lady Thomson wrote to Darwin, " Sir William has 
been, and is, so busy over endless things, University 
Commission, etc. etc., that he has written to the 
Master if they can do without him this time." He 

1 He wrote, on January 6, 1892, when the first machines were nearly ready 
for work : "I am much interested in what you tell me about the progress of 
the Niagara work. I am very glad that contracts are being made for the 
power, and I hope soon to hear of a commencement of its actual use having 
begun. I do not believe that alternating currents will be found to be the 
right solution of the electric transmission to a distance. I have no doubt in 
my own mind but that the high-pressure direct-current system is greatly to be 
preferred to alternating currents. The fascinating character of the mathe 
matical problems and experimental illustrations presented by the alternating 
current system, and the facilities which it presents for the distribution of 
electric light through sparsely populated districts, have, I think, tended to 
lead astray even engineers, who ought to be insensible to everything except 
estimates of economy and utility." 


had a prospect of being even more busily occupied ; 
for not only were the meetings of the Niagara 
Commission in prospect, but it was well known in 
the Royal Society that Sir George Stokes would 
resign the Presidency of that body in November, 
and the general consensus of the Fellows was fixed 
upon Sir William as the next President. 

St. Andrew s day, November 30, is the date fixed 
by the statutes of the Royal Society for the election 
of Council and of a new President. Sir William 
had long been marked out for this, the highest honour 
which scientific men in Great Britain can offer to the 
most distinguished of their number. He had had no 
fewer than ten important memoirs in the Philosophical 
Transactions ; he had been a Fellow since 1851 ; he 
had received a Royal Medal in 1856, and the Copley 
Medal in 1883. He was now to step into the Presi 
dential Chair, to occupy it for the five years which 
custom has ordained as the period of its occupancy. 

Sir William Thomson was now much more in 
London than in previous seasons ; and by reason of 
his position as President he was invited to many 
functions, such as the annual banquets of the Royal 
Academy of Arts, the Institution of Civil Engineers, 
and of other learned societies and other professional 
bodies. This necessitated many journeys between 
London and Glasgow, and his ability to sleep 
soundly while travelling at night stood him in good 
stead. He had other matters, too, to keep him 
busy. He had invented a new water-tap to super 
sede those which in domestic use gave so much 


trouble by dripping when worn, or when their 
packing had hardened with age ; and he was 
troubled by threatened litigation over his patent 
compass. Also his thoughts were running on the 
old problems (see page 157) of electric and magnetic 
screening. On this topic he wrote an inquiry to 
Lord Rayleigh on March 16, 1891, adding the 
news : " My compass case is settled between the 
solicitors at complete surrender, plus ^500 towards 
damages and costs." He was to lecture in April at 
the Royal Institution on Electric Screening, and 
prepared to send to the Royal Society two papers 
on the same subject. Respecting the second of 
these he wrote on March 29 to Lord Rayleigh, 
saying that it would include the following matters : 

Let a closed copper shell (it need not be a figure of 
revolution) rotate about any axis. Let a second, en 
closing it, rotate about a second axis exactly perpendicular 
to the first. Let any magnet be held at rest inside the 
first shell. It will exert no influence on space outside the 
second shell if the rotations are sufficiently rapid. 

Variational action, if not too excessively rapid, pro 
motes electrostatic transparency. It promotes electro 
magnetic opacity. A sheet of black paper in ordinary 
hygrometric condition is a perfect screen against steady 
electrostatic force. If the force alternates with 
moderate frequency, say from 10 periods to 10,000,000 per 
second, the paper is no screen at all. If the frequency be 
greater than 200 X io 12 the paper screen is again opaque. 

On April 24 his students presented him with 
an address congratulating him on his election as 
President of the Royal Society. In acknowledging 
the presentation he said : " I have been a student 



of the University of Glasgow for fifty-five years 
to-day ; * and I hope to continue a student in the 
University of Glasgow as long as I live." 

April 24, 1891. 

This season he rented a suite of rooms at No. 
127 Ebury Street, London, from the end of the 
Glasgow session. Thence he wrote on May i to 
his sister Mrs. King : "We are going to-day to the 

1 This impression seems not to correspond accurately with the records ; 
for he matriculated in October 1834 (see page 8). The accompanying 
illustration, which appeared in the Daily Graphic of April 28, 1891, is repro 
duced by the courtesy of the proprietors of that journal. 


private view of the Academy, where we are de 
lighted to hear that Elizabeth [Miss King] has a 
picture. To-morrow we go to the opening of the 
Naval Exhibition, and, as P.R.S., I dine in the 
Royal Academy in the evening." 

A recent development in the kinetic theory of 
gases, known as the Boltzmann-Maxwell doctrine, 
had given him matter for thought of late. Accord 
ing to this doctrine the kinetic energy in a mass of 
gas under given conditions of pressure and tempera 
ture is distributed in equal proportions between the 
translatory motions of the molecules as they fly 
about in space and their rotatory motions within 
themselves. Sir William Thomson was unable to 
admit that this law was anything but empirical, and 
persistently disputed its foundation. Lord Rayleigh, 
on the other hand, was its stoutest upholder. There 
was much discussion between them, and many were 
the notes and postcards which Sir William sent, 
raising case after case to contest its generality. At the 
Royal Society on June n he stated for discussion a 
number of test-cases. He had written on June 6 to 
Lord Rayleigh a problem of this kind, and added : 

I am confining my " test-case " to placing it before 
the Royal Society for consideration ; and it is not this 
question, but the Baltimore molecule that is to constitute 
it. I am sorry you are not to be at Greenwich [at the 
Annual Visitation of the Royal Observatory] to-day. If 
you had come we might have got the question settled. 

The Board of Trade had recently appointed an 
Electrical Standards Committee to settle for legal 
purposes the denominations of Electrical Standards 


in the United Kingdom, and so give legislative 
weight to the decisions of the International Con 
gress of 1889. Sir William Thomson was naturally 
consulted in this matter. At the meetings of the 
Committee, from January to July 1891, he took an 
active part in the discussions, and in the examina 
tion of scientific witnesses. He was strongly in 
favour of making the standard ohm of solid metal. 
He opposed the acceptance of the Clark cell as a 
standard of electromotive force on the ground that 
it was not permanent. He also signed the supple 
mentary reports of 1892 and 1894. 

In referring to the ampere, Sir William Thomson 
said that the grave accent on the first "e" in the 
name should be omitted, as the word had now be 
come adopted into the English language. This was 
agreed ; and a reference to the Order in Council 
issued on August 23, 1894, will show that the law 
recognizes this to be the spelling. 

The season over, Sir William and Lady Thomson 
sailed for Madeira. Lady Thomson wrote on 
August 19 to Mrs. King, " William sits out all day 
under the trees very happy with his green book, and 
deep in a very difficult problem which he is working 
hard to solve! It is a grand time for him." 

On September i Sir William addressed to Lord 
Rayleigh a letter, dated " In a hammock, Camacha," 
Madeira, telling him of a manuscript he had sent to 
the Philosophical Magazine about a model with a 
jointed pendulum and a jumping clock which is "a 


perfectly decisive test-case against the Boltzmann- 
Maxwell doctrine " ; and adds : " This (Madeira) 
is perpetual Senate-house. Book-work and problem 
papers to be done with no books of reference." 

By September 12 they were back in England ; but 
the British Association meeting at Cardiff was over. 

In November 1891 he was repeatedly writing to 
Lord Rayleigh on a mathematical matter Hill s 
determinant on which he had doubts. To one of 
these notes he added a postscript : " I have been 
seeing Parker s great electric factory at Wolver- 
hampton (now belonging to the Electric Construc 
tion Co.). It is splendid far ahead of anything I 
have seen before." To another letter was appended 
a paragraph on the installation, on November 26, of 
Mr. A. J. Balfour as Lord Rector at Glasgow, when 
he delivered an address on Progress. " Prince 
Arthur has been most charming and potent in philo 
sophy yesterday and politics to-day. His reception 
was splendid ; classes and masses unitedly enthu 
siastic and appreciative." Mr. Balfour stayed with 
Sir William in the University. There was after 
wards a banquet in the City Hall, at which, replying 
to the toast of the University, Sir William spoke of 
himself as " a child of the University," and described 
the changes in its constitution which himself had 
witnessed by the action of two successive Royal 
Commissions. The next day, acting as the spokes 
man of a number of friends and subscribers, Mr. 
Balfour presented to the University a portrait 
by Herkomer, of Sir William, which had been 


subscribed for in commemoration of his election 
as President of the Royal Society. In presenting 
the portrait Mr. Balfour eulogized the unceasing, 
the astonishing activity of mind which had secured 
him the gratitude of this generation and the title to 
fame in the Generations to come. Sir William, in 


acknowledging the presentation, said : 

I have felt that to live in the University of Glasgow, 
and to remain at the University of Glasgow to the end 
of my life, is the career that has been most of all con 
ducive to my happiness and appropriate to give me the 
means, the position, and the surroundings to provide for 
me the surroundings that have allowed me to go on 
with my scientific work. The facilities that the Uni 
versity has given me for experimental research, the 
splendid assistance that I have obtained voluntarily, 
offered voluntarily, and continued voluntarily, and 
persevered in through a great deal of hard and straining 
work voluntarily, by students of the University of 
Glasgow, has done more for me than words can tell, and 
without which it would have been impossible for me to 
realize any of the results which have been spoken of in so 
appreciative a manner to-day. I can only say, in the name 
of Lady Thomson and myself, that we are deeply grateful. 

Sir William s Presidential Address to the Royal 
Society on St. Andrew s day dealt with the most 
recent geodetic observations, in which certain 
changes in the position of the axis of rotation 
of the earth s globe had been detected. He also 
spoke of the recent Faraday centenary, and of the 
relations between the Royal Society and the London 
County Council in the matter of purity of water- 
supply. A note of personal reminiscence was struck 
in the following paragraph : 


The name of Becquerel has been famous in science 
since the days of Biot, Davy, De La Rive, Faraday, 
Ampere, and Arago. I well remember going to the 
Jardin des Plantes, in Paris, in January 1845, with an 
introduction from Professor James Forbes to Antoine 
Cesar Becquerel, who, even at that remote time, was a 
veteran in physical science ; and finding him in his 
laboratory there, assisted in work regarding electrolytically 
deposited films on polished metallic surfaces and their 
colours, by his son Edmond, a bright young man who 
had already commenced following his father s example as 
an active worker in experimental physics. . . . 

There was a little family dinner party that 
Christmas at the University in Sir William s house, 
at which his sister, Mrs. King, and Professor James 
Thomson were present. Mrs. King sent to her 
daughters an account of it : 

We had a lively dinner yesterday. Uncle James and Uncle 
William were very bright, and it was most amusing and interest 
ing. The question of the franchise for women, and the action of 
New Zealand in the matter, arose, and Uncle James referred to 
Anacreon s opinion of women. Uncle William challenged him 
to quote, and Uncle James recited the ode in Greek, and then 
translated for the benefit of the unlearned. It enumerated the 
gifts of the gods to various creatures, as the lion, the horse, 
etc. etc. to Man courage, power, wisdom to Woman beauty, 
which is stronger than all and can vanquish all. There was a 
great deal of the gaiety and wit of the College parties in the 
olden time that I remember so well, and yet there were only the 
Florentines [the James Thomsons]. There is certainly a great 
deal in this house to quicken one s wits. An interesting man, 
an electrical friend of Uncle William s, took tea here yesterday, 
and I listened with extreme interest to their talk, and watched 
Uncle William s keenness of perception and brilliance of inspira 
tion. I do enjoy this sort of thing. 

This was the last time that the two brothers and 
their sister were together. 



NEW YEAR S DAY, 1892, brought the announcement 
that a peerage of the realm had been conferred by 
Queen Victoria upon Sir William Thomson. The 
offer of this honour was made by the Prime Minister, 
Lord Salisbury, in a private and personal letter 
written with his own hand. It was couched in very 
friendly and personal terms, expressing the anticipa 
tion that the influence of the eminent man of science 
in the House of Lords would be a great access of 
strength to them, especially on certain subjects in 
which their Lordships were not particularly strong. 
The announcement was received with general satis 
faction in the public press, as a well-earned recogni 
tion of the pre-eminent position which Sir William 
Thomson by common consent held in science. 

The Times spoke of his " unquestioned distinction." The 
Daily Telegraph hailed him as " universally regarded as the first 
physicist, and one of the profoundest mathematicians, most 
suggestive thinkers, and most original inventors of the age." 
The Daily News spoke of his " European reputation as a man of 
science before he became President of the Royal Society," but 
hinted that he had other claims upon the present Unionist 
Government by reason of the very prominent part he had taken 

VOL. II 905 Y 


on behalf of the Liberal Unionist cause. The Globe, after 
declaring that Science has not generally been hitherto recognized 
as leading to the House of Peers, and that there were " many 
reasons why it should not, like the high careers of government, 
statesmanship, and high command, be made a regular highroad 
thither," added patronizingly that " it should not be without its 
representatives, when exceptionally qualified, as is assuredly the 
case in respect of Sir William Thomson." It quoted the opinion 
of Faraday that a great man of science could not be honoured by 
a title any more than a great poet ; but added that it was surely 
better to have men of intellect in the peerage than men of money. 
The Spectator described him as " the first man of science, we 
think, who ever received the distinction of rank for work in that 
domain." The Birmingham Post observed that the peerage con 
ferred on Sir William Thomson " is awarded for work about which 
there can be no question as to its extent or character. Not for 
services connected with the destruction of human life, but for 
those which elevate its character, enlarge its capacities, and in 
crease its happiness, the new peer has deserved his honour." 
The Manchester Examiner considered that there was a certain 
appropriateness in the destiny by which Lord Tennyson owes his 
peerage to Mr. Gladstone, and Sir William Thomson his to Lord 
Salisbury. "The man of words and the man of deeds both 
being men of ideas are again placed in contrast with each 
other." The Scottish newspapers, without exception, applauded 
the elevation to the peerage of one so highly esteemed throughout 
Scotland. " A peerage has at length been conferred upon a 
scientific man because he is a scientific man," said the British 
Medical Journal. -- 

Sir William was himself sincerely pleased with 
the token of official appreciation which thus had 
been publicly offered to him ; and there were great 
rejoicings at his house in the University. But 
rejoicings were strangely mingled with sorrow, when 
the very next day brought from Madeira news of 
the death of Mrs. Blandy, the mother of Lady 
Thomson. Mrs. King, arriving on January 3rd to 
congratulate her brother, found two piles of letters 
on the table, condolences and congratulations alike 
testifying to the sympathy and regard of friends and 


relations. Already the question of selecting a title 
had been discussed. The name " Kelvin, " taken 
from the Kelvin River, which winds its way through 
the Kelvin Grove below the (new) University build 
ings, had been favoured by those most concerned ; 
and, when his sister independently suggested it, Sir 
William, turning to his wife, said : " Did you hear 
that ? Elizabeth thought of it too ; Elizabeth agrees 
with us ; that decides it ; it shall be Lord Kelvin ; I 
will write to Lord Salisbury at once." Mrs. King 
wrote to her elder daughter : " Uncle William showed 
us many of the letters he has received ; the kind 
tone of all goes to his heart and fills him with happy 

A fortnight later Lord Sandford, visiting Glasgow 
as one of the Scottish University Commissioners, 
called at Sir William s house, and took tea with them. 
His father had been Professor of Greek in Glasgow, 
before Lushington, and little William Thomson had 
attended his classes in 1834-35. As boys they had 
played together on the banks of the Molendinar 
Burn, which flowed through the old College Green. 
Now they renewed their childish reminiscences, 
and Lord Sandford promised to act as one of the 
peers to introduce Lord Kelvin to the House of 
Lords when he should attend in his robes to take 
the oath of allegiance. His other introducer was to 
be Lord Rayleigh ; but the patent of peerage was 
not yet issued. 

Lady Thomson had written on January 6th to 
George Darwin : 



MY DEAR MR. DARWIN You will probably have 
heard before this that our joys and sorrows have come 
very near together, and so will forgive my not having 
written to you sooner to thank you and Maud for your 
very kind congratulations. The day after we heard of 
the Peerage we heard by telegram from Madeira of my 
mother s death it came upon us as a great blow, as we 
had been having letters from her up to two days before 
the telegram, telling us how well she was keeping. Every 
body has been so kind and said such kind words to us 
over this honour to Sir William that we have been quite 
overpowered. We have no new name yet. We have 
proposed Kelvin as being connected with Glasgow and 
the University, and not being too territorial but it waits 
the Queen s sanction. So in the meantime we are still 
Sir Wm. and Lady T. Yours most sincerely, 


Sir William had, meantime, written to various 
friends Lord Rayleigh, Dr. J. Hall Gladstone, and 



DEAR LORD RAYLEIGH I enclose C. s paper, which, 
if you approve, may be put in type for the 2ist, with 
slight pencil corrections I have made. It is scarcely 
worth while sending it back to the author for his 

I had a very bad time all the holidays over 

(a -f- /3 cos #4-7 cos 2x + . . .) = o. It works out 

beautifully, and with great ease for all values of a and (3 
(unless a is too very great), where 7 = 0, etc. But with 
anything beyond a + /3 cos x I don t yet see anything 
satisfactory on the plan of which I wrote to you. Yours 
truly, x ( ? x = Kelvin). 

[jP.^S.] With best wishes for the New Year from my 
wife and myself to you and Lady Rayleigh. 



Jan. 9/92. 

MY DEAR GLADSTONE I thank you heartily for your 
kind congratulations, and for what you say of science in 
connection with them. 

We have proposed " Kelvin " as the title for the sake 
of association with the University and city of Glasgow : 
but till the Queen approves nothing can be decided. 

I am very glad to hear you are all well, in these trying 
and dangerous saturnalia of microbes. 

Lady Thomson joins me in kind regards to all and 
best wishes for the New Year. Believe me, yours very 
sincerely, WILLIAM THOMSON. 

February 13, 1892. 

DEAR LORD RAYLEIGH I suppose the Bakerian 
Lecture l will be taken on Thursday the i oth of March, as 
that has been fixed for the Council meeting, and I shall 
be present. If, however, it is more convenient to take it 
on the 1 7th, you could do the reading and exposition 
at least as well as I. It will be fully written out and 
illustrated with at least two large diagrams. My brother, 
though he is not able for much work or use of his eyes, 
hopes to have the paper complete before the end of 

Will you be inclined to dine at the Royal Society 
Club on Thursday evening next ? I would like to do so, 
and if you would also we might have some better oppor 
tunity than the business at Burlington House allows of 
talking over non-official questions, and particularly high 
frequency and high potential. 

Was Tesla s light in vacuum tubes more brilliant than 
that of ordinary vacuum tubes excited by coils capable of 
giving sparks half a foot long? I can conceive of its 
being so, because of the greater time-integrals of the 
+ 100,000 volts and of the 100,000 volts than that of 
the high potential of one sign in the ordinary induction 

1 On the Grand Currents of Atmospheric Circulation, by Professor James 
Thomson. See p. 918. 


coil illuminating vacuum tubes. It seems to me, in short, 
that the time -integral of the light will be greater and 
therefore the appearance brighter than with induction 
coils : but not greater, that I can at present see, than that 
of vacuum tubes lighted by an ordinary electrical machine 
giving 100,000 volts. 

The marvel to The Times and others is there being 
no wire going through the glass, but the reporters can 
scarcely be expected to know of the electric light by the 
ordinary induction coils with nothing but plates of tin 
foil outside the glass and no electrodes going through the 
glass, though this is, I suppose, one of the earliest things 
known about the electric light in vacuum. 

The most interesting thing to me in what I have seen 
in the report is the impunity of touching one electrode in 
Tesla s arrangement. . . . Yours truly, 


P.S. Tesla s light in ordinary vacuum tubes, and in 
tubes containing Crookes s pieces of Iceland Spar, toasted 
shells, etc., will be time-integral of what we see (shadows 
and all) with the current from an ordinary electric 
machine, or from induction coils, with current alternately 
in opposite directions, but long enough in each direction 
to let us see the peculiar effect. The difference of the 
effects in the two directions is, of course, integrated out 
in Tesla s light. 

You will see in Nature, Jan. 6, 1 88 1, vacuum tubes 
without electrodes by J. Bottomley ; and a second note 
on the subject in Nature of Jan. 13, 1881. I see Glaze- 
brook (" G." in Nature of this week) seems to think 
vacuum tubes without electrodes a novelty. J. Bottomley 
long ago in his lectures showed a completely closed glass 
vessel of vacuum glowing when he held it in his hand 
above the spark between two poles of a Ruhmkorff. 


DEAR LORD RAYLEIGH Have we (R.S.) never given 
Crookes anything except F.R.S. ? If not, I think we 
ought to give him the best we can (? a Copley). His 



torrent of particles, toasted shells, and Iceland spar con 
verted to malachite and emeralds and rubies and topaz 
(Iceland spar), and his radiometer and wheelbarrow, etc. 
etc., are really the greatest things, by far, in deep-going 
physics of the nineteenth century. Yours, 


On January 28 Sir William Thomson presided 
at a meeting of the West of Scotland Liberal 
Unionist Association. 

In his opening remarks the Chairman said the pros 
pect of another struggle was now imminent. They 
should enter upon that struggle not at all discouraged. 
Twenty Rossendales could not discourage them. They 
had that best of all foundations for courage, a good cause. 
The course of the past six years had proved, every month, 
every year, that they were right in 1886. He could not 
believe so ill of his countrymen as to think that a majority 
of them could now be found to send representatives to 
Parliament pledged to whatever bill Mr. Gladstone might 
bring in. It would be an awful grief to every person 
who valued the prosperity of this country and the happi 
ness of Ireland, and who distinguished between right and 
wrong, should there be such a majority. It would be 
intolerable for Ireland not to be fully represented in the 
Imperial Parliament. Let them give every possible 
facility for the Irish people to manage their own local 
affairs, but they must have Irish co-operation in the 
Imperial Parliament. They had every confidence that 
right would prevail over wrong in the long-run, and reason 
over unreason. 

At a meeting of electors of the College Division 
of Glasgow, to promote the candidature of Sir John 
Stirling Maxwell, the Conservative candidate, on 
February 4, Sir William Thomson, in moving a 
vote of confidence, took occasion to defend the 
policy of Mr. Balfour as Chief Secretary for Ireland. 


It was now known that what was wanted to cure the 
ills of Ireland was good, honest, resolute, kindly govern 
ment. He ventured to say that to-day Mr. Balfour was 
the most popular man in Ireland. Notwithstanding the 
torrents of opprobrious epithets hurled at him by some 
Irishmen, Mr. Balfour had not turned one hair s-breadth 
from that path that had put Ireland into a condition of 
peace and prosperity. 

Sir William was in London on February 19 to 
open the electrical engineering laboratory which 
had been founded at King s College by Lady 
Siemens in memory of her late husband. In 
making the formal presentation on behalf of Lady 
Siemens he said that he was probably the oldest 
friend of Sir William Siemens amongst those 
present ; and he referred to his achievements and to 
those of his brother, Werner von Siemens, and of 
their brother-in-law, Professor Lewis Gordon, in the 
scientific application of telegraphy, and in the laying 
of submarine cables. Electrical engineering had in 
one respect an advantage over other branches of 
engineering it had begun on a thoroughly scien 
tific foundation. Beginners in modern electrical 
engineering thoroughly knew their science before 
they began practical work. What had grown in 
several thousand years in ordinary mechanical 
engineering, had come into existence in the case 
of electricity in as many days or weeks. Thus it 
was that this creation of the nineteenth century 
could hold its own with all the best mechanical 
engineering in the world. The development of 
the "dynamo" (the name given by Sir William 



Siemens) was largely owing to the investigations 
of the brothers Siemens. 

The same evening Sir William gave a discourse 
on Motivity to the Peterhouse Science Club, of 
which he had been elected president. A large 
gathering of scientific and mathematical visitors 
attended in the Combination Room of that ancient 
house. The lecture consisted mainly of a historical 
account of the theories of conservation and trans 
formation of energy. " Motivity " was in effect 
the operation of " available energy," as distinguished 
from such portions of molecular energy (in the form 
of heat) as cannot be employed in producing 
mechanical work. 

On February 23 Sir William Thomson was 
gazetted as Baron Kelvin 1 of Largs, in the county 
of Ayr. He took his seat in the House of Lords 
on February 25, being introduced, with the pre 
scribed ceremonies, by Lord Rayleigh and Lord 
Sandford. Those who have not witnessed the 
introduction of a new peer can scarcely conjure 

1 Lord Kelvin s change of designation was regretted by some who honoured 
the name of the man who had achieved so much. M. Taine, the distinguished 
litterateur, asked Mr. J. E. C. Bodley to explain something very curious. " I 
suppose it is still considered an honour to sit in your House of Peers ; but why, 
as a penalty for doing so, should my friend Sir William Thomson, whose reputa 
tion belongs to Europe and not to England alone, bury his illustrious identity 
in an unknown title ? Even if he had followed the example of Tennyson and 
Macaulay, and called himself Lord Thomson, that would not have been dis 
tinctive enough ; he was celebrated as William Thomson, and he ought to 
have called himself Lord William Thomson." " I explained," says Mr. 
Bodley, " that that style could not be applied to a peer, as it indeed indicated 
that the person so addressed belonged to a certain small section of commoners." 
"Well," said Taine, "it is another peculiarity of the British constitution." 

About the same time a foreign electrician of distinction wrote to the late 
Professor Ayrton to ask him who this person Kelvin was, who was claiming 
to have invented the galvanometer that all the world knows to have been 
invented by Sir William Thomson. 


up the scene when he and his supporters, clad in 
their gorgeous robes, and preceded by the Gentle 
man Usher of the Black Rod, the resplendent 
Garter King of Arms carrying the patent, the Earl 
Marshal, and the Lord Great Chamberlain, troop 
into the House, bowing thrice ; and the new peer, 
kneeling, presents his writ to the Lord Chancellor 
and retires to the table, while the clerk reads the 
patent and the writ. The Oath is then administered 
to the new peer, and he signs the Test-roll, when 
he and his supporters bow first to the Cloth of 
Estate, a second time to the Bishops, and again to 
the House as he crosses it to take his seat. Being 
seated there between his supporters they must then 
bow thrice to the Lord Chancellor, " taking off 
their hats at each time of bowing " ; and when the 
Lord Chancellor returns the salutation, the new 
peer is conducted to the Woolsack to shake hands 
with its occupant. One wonders what Lord Kelvin s 
thoughts were during the performance. 

The following arms were assigned to the barony 
of Kelvin of Largs : 

ARMS. Arg. , a stag s head caboshed, 
gules, on a chief, azure, a thunderbolt 
ppr. , winged or, between two spur revels 
of the first. Crest A cubit arm erect, 
vested, az. , cuffed arg. , the hand grasping 
five ears of rye, ppr. Supporters On 
the dexter side a student of the University 
of Glasgow, habited, holding in his dexter 
hand a marine voltmeter, all ppr. : and 
on the sinister side a sailor, habited, 
holding in the dexter hand a coil, the rope 
passing through the sinister, and sus 
pended therefrom a sinker of a sounding 
machine, also all ppr. Motto Honesty 
KELVIN. without fear. 

A dinner was given by the Glasgow University 



Club on the iQth of March to Lord Kelvin of Largs 
in honour of his elevation to the peerage ; when, 
under the chairmanship of Dr. Joseph Coats, they 
drank his health and commemorated his forty-six 
years of service to his University. 

In his reply Lord Kelvin spoke of the fostering influences of 
University life, and it was for more than mere instruction that he 
must always thank the Universities of Glasgow and Cambridge. 
In Glasgow there certainly was a very stimulating course. But 
there were differences in quality and subject in different 
universities. The thorough teaching of the University of Cam 
bridge, following on the initiatory study in which he had engaged 
in Glasgow, had been of the greatest possible value. He should 
be sorry to think that Greek was killed out of Scotch University 
studies by any preliminary examination. Universities ought not 
merely to be a means of advancing towards a profession and 
earning a livelihood. They should lead in this direction no 
doubt, but they should do more they should give a possession 
for life that rust could not corrode, nor moths eat, nor thieves 
break through and steal. Referring to the Atlantic cable, he 
remembered the services of his now venerable assistant Donald 
MacFarlane, and those of members of his volunteer laboratory 
corps in the old days, Professor Ferguson, and Messrs. Medley 
and Deacon, who had helped to hook up the lost cable of 1865. 


March 22/92. 

DEAR RAYLEIGH I am very glad to hear from 
Dr. Traill of T.C.D. that there is a prospect of your 
being at the Dublin Tercentenary, and his guest My 
wife and I are to be there and his guests in the College, 
so we hope you will be with us. The time is from the 
5th to the 8th of July. . . . Will Lady Rayleigh not 
come too, to T.C.D. ? Yours, KELVIN. 

P.S. I have instructed Potter, Admiralty Chartseller, 
to send you a copy of Weir s diagram, that you may see 
whether, as a most wonderful piece of " applied " mathe 
matics, it is not deserving of recognition by an award from 
the Gunning Fund of the R.S. It is quite unique as a 
graphic process for solving a problem of finding the value 


of a function of three independent variables (lat. of the 
place, decl n- of the sun or star, hour-angle). 

In April Lord Kelvin was nominated a member 
of the Joint Committee to consider private bills 
proposing electric railway schemes for London. 
On the nth of the month he gave an address on 
Navigation to the Mercantile Marine Association 
at Liverpool. Much of the lecture was technical, 
but the introduction and conclusion are of more 
than technical interest. He said : 

The remarks of the Mayor of Liverpool had revived his early 
recollections of Liverpool. His mind went back to 1842, when 
he visited the docks of Liverpool : his recollections of those days 
were principally of skysail rnasts and yards. He had a com 
panion a young officer in the service of one of the great firms 
trading to India who taught him, in his ignorance of seafaring 
matters, to look with admiration on the tall, tapering masts of the 
American ships then in Liverpool. There seemed to be some 
thing of American pride in those skysail yards, whilst the English 
ships in dock were contented with royals, never aspiring to the 
greater elevation. Yet they survived their American competitors, 
and practically ran them off the sea. There was something much 
greater than skysail yards now. There were three-masted and 
four-masted iron sailing ships carrying 3000 tons or more twice 
as much as any sailing ship of Liverpool could carry 50 years 
ago. There had been an enormous advance in the carrying 
business, owing to the prosperity of England ; and every part of 
the world was represented in Liverpool now as it was then : but 
England s sh?re was relatively much greater now than then. It is, 
however, no pleasure to us to think that our friends on the other 
side of the Atlantic declined so greatly in the work of carriage by 
sea. It was not due to want of ability and seamanlike qualities, or 
of appreciation of the management of ships at sea, or of the power 
to build the best kind of ships for the sea, that the Americans 
were so much off the sea, and confined their business to three- 
masted schooners sailing up and down the American coast. It 
was due to bad politics. Liverpool had always been to the front 
in sound politics in regard to that great principle of Liberalism 
free trade. People seemed to forget that free trade meant two 
things freedom and trade, both very good things. He had 


always thought that that kind of Liberalism which was represented 
by free trade had been an honour to England, to Lancashire, and 
to Liverpool. They might well be satisfied that Liverpool had 
played so great a part in promoting its results. Great changes 
had taken place since the period he had referred to. The greatest 
carrying work of the world was now done by steamers, and 
Liverpool was not behind the rest of the world. 

The bulk of the lecture was devoted to " lunars," 
Sumner s method of finding the position of a ship, 
the use of the globes in education, Weir s diagram, 
and the advantage of taking soundings. 

Every navigation school, for young or old, should always have 
a globe at hand, and the work should be done by reference to a 
globe, to explain the meaning of spherical trigonometry, which, 
without a globe to help, was as veritable a twisting and screwing 
of the brain, as severe a mental torture, as could well be con 
ceived. The " Use of the Globes " annulled the mystery of 
"great circle sailing" ; and was truly valuable to the navigator in 
helping him to judge as to permissible, or eligible, or necessary 
deviations from the great circle. With respect to dead-reckoning 
and trusting to it for the safety of the ships, he must say that it 
was literally true that more ships had been lost by bad logic than 
by bad logs ; and that had largely been promoted by Board of 
Trade findings in Courts of Inquiry. . . . Now that ships need 
not stop to take soundings, when they got within the loo-fathom 
line they should use the lead, and keep sounding every ten 
minutes or every five minutes, according to judgment, from hour 
to hour. If this had been done in some recent cases disasters 
would have been avoided. 

About this time, the Board of Trade, in draught 
ing electric -lighting orders, proposed to adopt the 
term " kelvin " as the name of the unit of supply, in 
place of the term " kilowatt-hour." Sir Courtenay 
Boyle communicated the proposal to Lord Kelvin ; 
but he put from him the suggestion in favour of 
the term " supply -unit," giving, amongst other 
reasons against the proposal, the ambiguity that 


might arise if a supply-meter were described as a 
" kelvin-meter." 

On the 8th of May 1892 Professor James 
Thomson died. 1 He had held the chair of En 
gineering at Glasgow from 1873 to l %%9* when, 
owing to failing eyesight, he retired. He had been 
active in science up to the last : his Bakerian 
lecture on " The Grand Currents of Atmospheric 
Circulation " having been read (by Lord Kelvin for 
him) at the Royal Society on March 10, 1892. 
Lord Kelvin, writing on May 12 to their brother 
Robert in Australia to tell him of the events, said : 
" James had been very well, and since last March 
feeling very happy that he had finished and com 
municated to the Royal Society a great work of 
years on the trade winds and other great motions 
of the atmosphere. He was still occupied with a 
continuation of work of this kind, in which he took 
great and never-failing interest, when he died." 
Lord Kelvin s sorrow was very real and very deep. 
Throughout their lives the two brothers had been 
associated together not only in much scientific work, 
but in closest personal association ; not a tinge of 
jealousy ever clouded their more than brotherly 
affection. In thermodynamics particularly their 
work was so closely related that it was not always 
easy to distinguish the parts due to each. Though 
Lord Kelvin was himself scrupulously careful to 

1 An appreciative memoir of Professor James Thomson, by his nephew 
Dr. James T. Bottomley, will be found in the Proceedings of the Glasgow 
(Royal) Philosophical Society > 1892-3, vol. xxiv. pp. 220-236. 


mention his brother s name in any matter that 
originated with him, his own fame is apt to over 
shadow the important contributions made by the 
elder brother. It has been quaintly said that William 
would not have been William without James, and 
that James would not have been James without 

Lord Kelvin, who had hurried to Glasgow to the 
bedside of his dying brother, was due to attend Parlia 
mentary and scientific committees later in the week, 
but wrote to Lord Rayleigh (then Secretary of the 
Royal Society) that he must put off the reading of 
a paper on electrostatic capacities till June. He 
added : 

I would like before the end of the session to com 
municate, from my brother, an explanation of the beams 
of light seen when looking with partially closed eyes at a 
lamp flame, unless we find that the explanation has been 
already given. They are usually, but as my brother 
showed me wrongly, attributed to some effect of the 
eyelashes. He explains them by the [capillary] curvature 
of liquid between the eyelids and the cornea. They are 
seen indifferently in virtue of lower or upper eyelid. Do 
you know anything l of this, or whether the subject has 
been treated by any one ? 

1 [I cannot forbear adding here a note of an incident illustrative of Lord 
Kelvin s personality, though it concerns myself. At the Conversazione of the 
Royal Society of June 15, 1892, Lord and Lady Kelvin were receiving their 
guests at the head of the staircase, and it came to the turn of Mrs. Silvanus 
Thompson and myself to be received. Lord Kelvin literally seized me, and 
hurriedly said to me, pointing to an electric glow-lamp hanging a few yards 
away, " Look at that lamp : now half shut your eyes : tell me what you see." 
I said, "I see irregular luminous streaks extending in somewhat oblique 
bundles above and below." " What are they due to?" he asked. "Oh, I 
have always supposed them to be due to the film of moisture at the edge of 
the eyelids, acting as an irregular cylindrical lens." "Who told you that? 
Where did you find that ? " he asked excitedly. But just then a hand was 
laid on his sleeve, and a gentle voice behind us said, " William, there are 


I shall come on Wed y night if possible : but my 
sister-in-law and two nieces are both very ill and I do 
not know if I shall feel able to leave. 

Alas, the sorrow was increased by the death of 
James Thomson s widow and of one daughter, 
within a week of his own death. 

On May 28, introducing the Duke of Devon 
shire at a Unionist meeting in Glasgow, Lord 
Kelvin told the audience that personally he spoke for 
the same reasons as those which, in 1886, impelled 
him to enter upon political subjects that were very 
far indeed from his ordinary and natural avocations. 

As an Irishman he felt then, as an Irishman he felt now, that 
a frightful damage was threatened against his native land : to 
take away Ireland from its grand position as a constituent equal 
member of the British Empire, to make it a naval and military 
station of the neighbouring island of England and Scotland. 
. . . He had many friends whom he admired and for whom 
he had the most sincere respect, whom he regretted to have 
unhappily followed Mr. Gladstone in that crazy departure from 
good political principles. . . . He was Irishman enough to like 
the Irish Parliamentary party ; to admire their mode of procedure 

people waiting." Later in the evening he resumed the subject, telling me 
how his brother, while lying in bed ill, had studied these apparent rays and 
given him this explanation ; and he asked me whether I had written anything 
upon the phenomenon. It was not till months afterwards that I found the 
following note printed in the Proceedings of the Royal Society, vol. Hi. p. 74, at 
the end of the paper of his deceased brother, which he had communicated : 
"Note by the President, of date June 1 6. I had asked many friends well 
acquainted with optical subjects whether they knew of this explanation of 
the luminous beams, and all said no until yesterday evening at the soirfe 
of the Royal Society, when Professor Silvanus Thompson immediately 
answered by giving the explanation himself, and telling me that he had 
given it to his pupils in his lectures on optics, as an illustration of a concave 
cylindrical lens. He did not know of the explanation ever having been 
published otherwise than in his lectures. I have myself looked in many 
standard books on optics, and could find no trace of intelligence on the 
subject. It seems quite probable, therefore, that of all the millions of 
millions of men that have seen the phenomenon, none within our three 
thousand years of scientific history had ever thought of the true explanation 
except Professor Silvanus Thompson and my brother."] 


in some respects ; to consider that according to their lights they 
were doing quite right. He thought their lights were false, and 
he thought they were doing wrong. A bill which took the Irish 
members out of Westminster and sent them to Dublin would be 
an unmixed evil to the British Constitution, an unmixed evil to 

The summer was a busy one ; for besides holding 
the Presidency of the Royal Society, and attending 
meetings of the Scottish University Commission, 
Lord Kelvin accepted the Presidency of the Institute 
of Marine Engineers, and on June 7 paid a visit to 
its premises in the Romford Road. He was also 
advising the Board of Trade as to Electrical 

He wrote to von Helmholtz : 

June 20, 1892, 

DEAR VON HELMHOLTZ Your letter of the ipth of 
May has remained too long unanswered : because I 
wished to have authority from the Board of Trade in 
answering it. It had been resolved to issue at the 
middle of the present month an Order defining, for 
practical purposes, standards of electrical resistance, 
current, and " pressure " (potential). I am now authorised 
by the Board of Trade to say that in deference to your 
wish, the proposed Order will not be issued until next 

The advising Committee of the Board of Trade in 
respect to Electric Standards (of which Rayleigh, Glaze- 
brook, Carey Foster, Ayrton, and myself are members) 
were unanimous in wishing that you, and one or more of 
your colleagues in the work of electric measurement, 
would come to the British Association, which meets in 
Edinburgh on the 3rd of August, and thus give us the 
opportunity of conferring on the standards to be adopted, 
and of coming to an agreement on all questions such as 
those referred to in your letter of May I pth. 



I was asked by my colleagues to do what I could to 
persuade you to come yourself. You know I would 
compel you to come if I could ! I hope the time will 
be convenient to you (more so than the later times of 
meeting which for many years back have been chosen 
for the B.A. meeting), and I wish very much that you 
would consider whether a trip to Scotland in August 
would not for one year at all events be as health-giving 
as Pontresina or elsewhere in the Alps. 

It will be a great pleasure to Lady Kelvin and myself 
if you and Mrs. von Helmholtz will come to Scotland 
and give us as long a visit at Netherhall as your time 
before or after the meeting in Edinburgh, or both before 
and after, will allow. 

With our united kind regards to you and your wife, 
and to (the now matronly) Ellen, I remain, yours always 
truly, KELVIN. 

P. S. For nearly a year I have been greatly exercised 
over the equation 


4- TT(*) = o 


where IT is such that TT(X + c) = TT(X) ; which occurs in 
connection with the question of the Stability of Periodic 
Motion. I have spent more time than I would like to 
confess on the case ir(x) = a + fi cos (x) ; and at last, 
within the last few days, I see my way to answer all 
those questions regarding it which I had felt difficult. 

The results are (to me) wonderful and exceedingly 
interesting. I hope soon to send you a rough proof in 
print. I believe we shall find that all periodic motion is 
essentially unstable. 

Various honours fell to Lord Kelvin about this 
time. On the occasion of the Galileo Tercentenary 
the University of Padua gave him the Doctorate of 
Natural Philosophy. He was also nominated by the 
Berlin Academy to receive the first Helmholtz Medal. 


He wrote again to von Helmholtz : 

July 12/92, 

MY DEAR HELMHOLTZ We are delighted that you 
and Mrs. von Helmholtz will come to the British 
Association, and Netherhall. I have written to Tait 
telling him that you are coming, and asking him to 
arrange about your being received in Edinburgh. 

I am very much pleased to be one of the first four 
Helmholtz medallists ! I have written to the " Akademie " 
expressing my thanks, but I feel that I must also thank 
you for having thought me worthy of so great and so 
especially interesting an honour. 

I shall be glad to do what I can to assist with 
the other Medallists in proposing to the " Akademie " 
candidates for new elections. 

My wife joins me in kind regards to you and Mrs. 
von Helmholtz, and I remain, yours always truly, 


P.S. We leave London this week, and hope to be in 
Netherhall soon after. 

In July came the Tercentenary Celebration of 
Dublin University, the brilliant ftes of which were 
attended by Lord and Lady Kelvin, who were 
afterwards entertained at Birr Castle by the Earl of 

On the last day of July Lord Kelvin unveiled at 
Stirling the memorial bust of Murdoch, the inventor , 
of gas-lighting, and gave an address on the work of 
that pioneer of road-engines. 

August 4 brought the meeting of the British 
Association at Edinburgh under the presidency of 
Sir Archibald Geikie, whose Inaugural Address 
reverted to Hutton s Theory of the Age of the 


Earth a topic which had claimed Lord Kelvin s 
attention (p. 605) when the Association met in 
Edinburgh in 1871. Sir Archibald now admitted 
that the age-long loss of heat which demonstrably 
takes place from both earth and sun, makes it quite 
certain that the present could not have been the 
original condition of the system. This steady 
diminution of temperature was no speculation, but 
fact. It pointed with unmistakable directness to 
that beginning of things of which Hutton and his 
Uniformitarian followers could find no sign. 

Lord Kelvin, in proposing a vote of thanks, 
referred to a conversation he had had with a dis 
tinguished geologist, after a former lecture of Sir 
Archibald s, when the geologist demanded for the 
age of the earth not one hundred million, or one 
thousand million, nor even a million million years, 
but would admit absolutely no limit. Then he 
continued : 

I have listened with very "great interest to the con 
clusions that we have heard this evening, and to the 
developments within these last thirty years, according to 
which geologists find it possible to hurry up the action 
without abandoning any fundamental principle of the 
Huttonian theory, except the perpetual motion and the 
want of a beginning ; how it is possible to understand a 
little more the evolution of what we see around from 
preceding states ; and how geologists are now struggling 
intelligently, and not denuding anything from any part of 
science. I am sure we all feel that geology has made 
great progress, dating from the Huttonian period of a 
hundred years ago, and that it has not been stagnant but 
has had its evolution, and has made great progress within 
the last thirty years. 


This meeting was notable for the presence of 
von Helmholtz and other foreign electricians who 
came to thrash out the disputed details about 
electrical standards, and who also participated in the 
proceedings of the Sections. Lord Kelvin himself 
read three papers : on the stability of periodic 
motions, on the graphic solution of dynamical 
problems, and on the reduction of degrees of 
freedom to the problem of drawing geodetic lines. 
The proposition to found a National Physical 
Laboratory was also discussed. 

A week later Lord Kelvin wrote to Lord 
Rayleigh : 

Aug. 23/92. 

DEAR RAYLEIGH I have been very hard on geodetics 
and dynamics, and just this morning got to the end of 
this particular affair most satisfactorily. 

I am getting near the end of all I can do for 
" instability," too. It has a bewildering variety of illustra 
tive cases. One of the clearest of all is the consequences 
of Mr. Gladstone s Home Rule Bill becoming law. His 
majority would be immediately reduced from + 40 to 40. 
The act would be repealed, and so on for ever, if " e " is 
real. If " e " is imaginary, one or two dissolutions would 
send Mr. Gladstone off to infinity. 

We had a splendid time in Edinburgh. Helmholtz 
(including Lindeck and Kahle) was most satisfactory as 
to units, and he and Michelson (and Glazebrook, who in 
about 20 words made M s. splendid investigation clear to 
those who, before he (G.) spoke, had not an idea what it 
was) and Smithells, by the condemnation of his "oxygen 
theory " which he elicited from Stokes and Helmholtz 
and Schuster, etc., etc., made the meeting about the best 
I have ever known in point of instructiveness. But I 


must say no more of it ; it would make you so unhappy 
not to have been in it. 

Their Excellencies were very good here also. He has 
well matured, and sound views regarding Mr. Gladstone 
and his doings. We got a great deal out of him, all 

I wish I had telegraphed to you urging you to come 
to Edinburgh. I wonder if it would have drawn ? Yours 
truly, KELVIN. 

The autumn was mostly spent at Netherhall 
with a constant succession of visitors to enjoy the 
hospitalities so lavishly offered within its walls. 
An intimate account of a visit by a grand-daughter 
of Mrs. King, Miss Margaret E. Gladstone (now 
Mrs. Ramsay MacDonald), affords a number of 
details which help to make up the picture of the 
life in Lord Kelvin s country home, as seen through 
the eyes of a naive young girl. The extracts kindly 
supplied begin with a reference to the British 
Association meeting of August. 

At Lord M Laren s I was taken down to dinner by Copeland, 
the Scotch Astronomer - Royal, a pleasant old gentleman, who 
talked about astronomy, etc. He told me, without knowing that 
I was related [to Lord Kelvin], that he had been dining there a 
few nights before, and when the Madeira wine was served, its 
flavour had reminded him of a visit to Madeira just about the 
time of Uncle William s marriage. This made him look up, and 
he caught Uncle William and Aunt Fanny raising their glasses to 
their lips and looking at each other from opposite ends of the 
table. He said he thought it such a pretty incident, just like one 
of Hans Andersen s fairy tales, 

In one of Uncle William s papers "On the Stability of 
Periodic Motion," it was very lovely to see him trying to balance 
the long pointer on the tip of his ringer. 

Helmholtz and Uncle William were inseparable, and both 
spoke a good deal in the sections, and Tait sat and smiled 
serenely at everything. 


At Netherhall (about September-October), I had a very nice 
time. ... As I was so long at Netherhall, I got to know them 
much better, and to be very devoted to them ; at least I don t 
like Uncle William when he is haranguing upon politics, as if 
there were no sense and no goodness on the Gladstonian side, 
and I should dislike it still more if I were on his side myself: 
but I admire his earnestness, and it is really that which carries 
him away. 

Generally the house was full of company : 24 different 
people stayed in it while I was there, and endless others came 
to dinner and tea and lunch. Aunt Fanny likes company very 
much ; and as for Uncle William it doesn t seem to make much 
difference to him what happens : he works away at mathematics 
just the same, and in the intervals holds animated conversation 
with whomever is near. They were both very good to me ; and 
the time I liked best of all was one day when there were no 
visitors at all, and we were quite by ourselves for about thirty 

Uncle William was busy with some great mathematical 
question ; and a side-issue connected therewith was the making 
of Mercator charts of objects of various shapes. An anchor-ring 
(shape of a curtain-ring) can be made into a single oblong sheet 
by being cut round the circumference and also at right angles. 
But to mercatorize, or skin, a double anchor-ring, or treble, or 
multiple, was more complicated, and for several days we all 
were employed on that problem. It was very amusing : Uncle 
William was always breaking out in the middle of meals, or 
driving, etc., " Margaret, I ve thought of a better way to skin 
the double anchor-ring," and then describing it. We had no 
double anchor-ring, so I suggested getting one made in dough; 
and I believe they had great fun in getting the cook to make a 
loaf like this >^ -s-x-x ; but I was out on a steamboat excur 
sion at the \^~^-^) time. When I got home I found Uncle 
William wanted to cover this all in one piece 

somehow ; so I got my paint-box, and we painted the loaf Prus 
sian blue, leaving white lines where it must be cut. That blue loaf 
was Uncle William s constant companion for some days ; and 
Aunt Fanny said, a fortnight ago, that it was still knocking about 
the drawing-room at Netherhall. Some of my suggestions were 
squashed at once because they didn t fit the high mathematics of 
the subject ; the mathematics went on vigorously in the " green 
book." That "green book" is a great institution. There is a 
series of "green books" really notebooks made specially for 
Uncle William, which he uses up at the rate of 5 or 6 a year, 
and which are his inseparable companions. They generally go 


upstairs, downstairs, out of doors, and indoors, wherever he 
goes ; and he writes in his " green book " under any circum 
stances. Looking through them it is quite amusing ; one entry 
will be in the train, another in the garden, a third in bed before 
he gets up ; and so they go on, at all hours of the day or night. 
He always puts the place, and the exact minute of beginning 
an entry. 

Another thing on Uncle William s mind during my visit, 
especially at the beginning, was his stop-cock patent. He worked 
at a stop -cock whenever he was within a few hundred yards 
of one. It was strange ; for when I was staying there eight 
years ago, he and Uncle James were always running about the 
house with taps in their hands and discussing them. It gives 
one rather a common-sense way, or scientific way, of looking at 
things to stay with Uncle William : you begin to feel that every 
thing has a reason, and that that reason may be found out ; and 
things should not be slurred over, or left to chance, when you can 
direct them by taking a little trouble, and using a little thought. 

In September and October Lord Kelvin had 
two letters in Nature on the problems of " Merca- 
torizing." He wrote to Lord Rayleigh on this, 
saying that both Jellett and Maxwell were " wildly 
adrift" as to lines of flexure. He and Lady Kelvin 
were to pay a visit to Inveraray, " where I expect 
to find the Duke full of fight, which will be very 
agreeable and interesting." 

Tennyson died on October 6, 1892. At his 
funeral on October 12, in Westminster Abbey, 
Lord Kelvin was one of the twelve pall-bearers, 
along with Lord Salisbury, Lord Dufferin, the 
Duke of Argyll, Lord Rosebery, and the Master 

of Trinity. 


AYRSHIRE, Oct. 16/92. 

DEAR RAYLEIGH The appointment 10.30 A.M. 
Oct. 27, for Board of Trade Committee on Electric 


Measurement, holds. Cardew writes me that he will have 
a reminding circular sent. 

The anti-mercatorizing (the reduction to drawing 
geodetic lines) of the problem of a pair of masses con 
nected by a spring, moving in the line joining them, 
between two soft planes, is curious. It may possibly 
help towards the question of distribution of kinetic energy 
between that of their c. of g., and of their relative motion. 

We were greatly delighted with the victory by 3 of 
yesterday. What do you think of Mr. Morley s beginning? 
The dullest of apprehension are beginning to learn, but 
the most shocking part of the thing is that such object 
lessons are required to teach them. What does Mr. 
Gladstone deserve? The 22 cows with tails cut off, the 
murder, and the effects of the assault on Inspector Lily 
are a first instalment of the grand sacrifice to his vanity, 
entailed by the resolution of electors to give the old man 
another chance. 

I hope Mr. Balfour is getting a good rest, and getting 
it fast, because it seems less likely to be long than it did 
6 weeks ago. Yours, KELVIN. 

November 30 brought round the annual meeting 
of the Royal Society. In his address the President 
spoke of magnetic storms, terrestrial magnetism, 
and the elastic yielding of the earth. A week later 
he read a paper on the velocity of the cathode 
stream as observed in highly -exhausted vacuum- 
tubes, and followed this by a letter to Sir William 
(then Mr.) Crookes : 

Dec. 19, 1892. 

DEAR CROOKES I am exceedingly obliged to you 
for the copy of your paper which you sent me. I have 
been studying it in the large volume of Transactions, but 
it is much more convenient and really more useful to have 
the separate copy. 

Have you any measurement of the pressure on the 


metal disc produced by the cathode stream ? I have 
great difficulty in seeing how the force of the magnet can 
suffice to produce the curvature of the trajectories which 
you have found. 

Have you ever found that the curvatures are less 
where the stream leaves the negative electrode, and 
greater at the greater distances ? as might be the case 
if the stream experiences resistance such as you suggest. 
I suppose quite a moderate magnetic force suffices to pro 
duce a sensible deflection. My difficulty is to find that 
any conceivable amount of transverse force exercised by 
the magnet upon the observed portion of the cathode 
stream can be large enough to produce the observed 
curvature, in a stream of which the momentum suffices to 
produce such pressure as is produced on a vane or other 
fixed surface on which they impinge. Yours very truly, 


Prescot, near Liverpool, had recently witnessed 
a revival of the watchmaking industry, by the 
establishment of the factory of the Lancashire Watch 
Company. Here, on January 12, 1893, at a dinner 
celebrating the extension of the works, Lord Kelvin 
proposed the toast of success to the undertaking. 

Personally, he said, there was nothing in the whole of 
mechanism in which he took more interest than a watch. He 
was quite sure the Lancashire Watch factory was going to 
demonstrate that good Englishmen and good English work 
wanted no protective duties to keep them to the very front, and 
to make them successful in the way of finding customers who 
would pay for the work and take pleasure in its possession, not 
only in England, but all over the world : " Overcome your 
enemies with well doing." 

He had been all his life engaged more or less in scientific 
experiments on measurement and on instruments of precision. 
They were thankful if in electrical instruments of precision they 
could attain an accuracy of ^ or -^ per cent ; but what did 
watchmaking do ? The commonest, cheap, good watch from the 
Prescot works would keep time to a minute a week, which was 
something like y^- per cent of accuracy. 


He need scarcely say to those present that no workmen could 
get good wages by saying that they " must have them," irrespec 
tive of whether they produced good work and plenty of it. Good 
wages for all, and the best wages for the best, was a fair and good 
law; and all the trades unions in the world, and all the legislation 
by Parliament, would never undo that law of nature. 

At the end of January 1893 a slight attack of 
pleurisy following a chill caught at a concert, kept 
Lord Kelvin in bed for several days, and prevented 
attendance at the opening of Parliament. He 
occupied his enforced leisure by working at hydro 
dynamics, " making hay while the sun shines," as 
he wrote, but adding, " I hope this kind of hay 
making will only last a day or two more." 

In March occurred the trial of the notorious 
swindle of the Harness Electric Belts. Lord Kelvin, 
at considerable personal trouble and expense, came 
forward to give evidence on the worthlessness of 
the much-advertised article. 

At the Royal Academy banquet on April 29 
he responded to the toast of Science, which, he said, 
some people considered austere, but which was full 
of wonders. Science was not an entgotterte Natur, 
a God-forsaken nature, a soulless nature, with only 
force and light, chemicals and crystals. Science 
brought us to the threshold of life, and knew its 
own incapacity to subject life to the laws of force 
and electricity. A natural scene without any life in 
it would lack interest ; life would give it interest, 
dignity, and beauty. 

He was busy all that spring with molecular 
physics and problems involving the principle of 


least action. His Royal Institution discourse on 
" Isoperimetrical Problems," and the Robert Boyle 
Lecture in May at Oxford on the " Molecular 
Tactics of a Crystal," are reported elsewhere (see 
pp. 1053, 1054). His crystal models were shown at 
the soirees of the Royal Society. 

In June he took part in the Jubilee dinner of the 
Cambridge University Musical Society, of which 
(p. 69) he had been one of the founders ; and was 
present at the Jubilee Concert where Max Bruch, 
Tchaikowsky, Saint -Saens, Boito, and Professor 
(now Sir Charles) Villiers Stanford took part in 
rendering or conducting their own works. 

Many banquets and reunions were attended this 
season, including a Ministerial banquet at Downing 
Street. July over, they went down to Netherhall 
to rest till the Home Rule Bill should come up to 
the House of Lords. A trip to Aix-les-Bains for 
Lady Kelvin s health was arranged for the autumn 
" though Lord Kelvin hates it ! " as she wrote to 
Darwin ; adding, " Lord Kelvin is busy with the 
molecular tactics of cleavage planes and faces of a 
crystal, and he wishes you were here to help." But 
the August holiday was saddened by the sudden 
death of Lord Kelvin s brother-in-law, Alexander 

With September came the debates in the House 
of Lords on the Home Rule Bill. While Viscount 
Castletown, a Liberal Unionist, was speaking 
against the Bill, the House was startled by a most 
unusual sound. Lord Kelvin, sitting immediately 


below Lord Castletown, was so carried away by his 
approval of the speech that, forgetting that the 
orthodox method of approval consists in shouting 
" Hear, hear," he vigorously clapped his hands, and 
almost petrified other peers who sat near him by 
the unaccustomed demonstration. The Bill was 
defeated on the second reading, but Lord Kelvin 
had left for Aix-les-Bains. 

In October Lord and Lady Kelvin were in 
Paris, where he read to the Academy of Science 
a paper on piezo- electricity, returning early that 
he might open the Blackpool electric lighting 
station on October 14. He was going to Cam 
bridge for the statutory Fellows meeting at Peter- 
house, and wrote beforehand to Professor Ewing : 

LONDON, Oct. 27/93. 

Do you still have magnetic molecules in large numbers, 
ready placed on points and stands, or easily so placed, 
just to show to any one looking direct without lantern 
what they do? I want to help myself about crystals by 
looking at them. If without too much trouble you could 
let me see them some time between 9.30 to-night and 
I 2 on Monday, when I have my College meeting, I shall 
be much obliged. Yours, KELVIN. 

On October 28 he visited the Leys School, for 
the opening of the new science laboratory, when he 
delighted the boys by advocating the free use of 
translations in learning classics, so as to get more 
time for science. There were more political meet 
ings and speeches in November, and then came 
the Royal Society anniversary. The Presidential 
Address on the researches of Hertz and of Crookes 


is considered elsewhere (p. 1058 infra). It fell to the 
President also to present the Copley medal to Sir 
George Stokes. He accompanied the presentation 
by a brief but masterly summary of Stokes s achieve 
ments in physics, dwelling particularly on his 
accurate measuring work, his codification of the 
optical laws divined by Huygens and Fresnel, and 
his clue to the dynamics of the undulatory theory of 
i light. 

On December 8 Lord Kelvin unveiled the fine 
statue of Joule in the Town Hall of Manchester, 
and delivered the striking address on Joule s work 
which is reprinted in Popular Lectures, vol. ii. p. 
558. (See also Nature, vol. xlix. p. 164.) 

Writing a few days later to Lord Rayleigh, to 
arrange for the reading in January of a paper on 
the Homogeneous Division of Space, Lord Kelvin 
briefly narrated how, since the defeat of the Home 
Rule Bill, he had been to Aix, was busy with three 
patents and with crystal models ; and he concluded 
with Christmas greetings. Lord Derby, with whom 
so many Christmas holidays had been spent, had 
died in April. Henceforth Christmas days were 
passed at Netherhall. 

Many were the speeches made by Lord Kelvin 
in the year 1894. In January he presented the 
prizes at the Blackburn Technical School, and spoke 
on the aims of education and the right attitude 
to take toward foreign competition in skilled in 
dustries : if foreigners do well, let Englishmen do 
better ; but to prevent the people of this country 


from exercising their good judgment in buying in 
the best and cheapest market would be grossly 
unfair. In February he made two speeches to 
Unionist associations, and on the 23rd of that month 
presided at a dinner at Birmingham to celebrate 
Founder s Day of the Mason College. He urged 
strongly that a case had been made out for a Mid 
land University or a University of Birmingham. 
" Birmingham should take the lesson of James 
Watt 1 to heart, and remember that a University 
would not only be a crown of glory to the city, but 
would be of continual practical benefit to the work 
shops of the mechanics." In March he spoke at 
the Civil Engineers. In April he opened Coat- 
bridge electric light works ; spoke at two Unionist 
meetings, at the Mechanical Engineers, and at the 
Institute of Journalists. In May he opened the new 
Engineering Laboratory at Cambridge organized 
by Professor Ewing ; spoke at the Institute of 
Chemistry on scientific cataloguing and indexing ; 
and at the Royal Society on the electrification of 
air. He had been busy, too, on the theories of the 
shrinkage of the globe as it cools, and wrote several 
letters to George Darwin on the subject. One of 
these, on March 29, ends thus : 

I have had a very broken time with various engage 
ments, and finishing up our Glasgow Session, and an 
Oxford lecture (of last May) on Tactics of Crystals, for 

1 James Watt, in 1756, was not permitted by the trade combinations of 
Glasgow to set up a workshop in that city, but found a place in Glasgow 
College, in the post of mechanician to the University, which still possesses 
some of his models. Later he founded in Birmingham the firm of Boulton 
and Watt. 


which I am now in the painful position of meeting a bill 
overdue, under threats from successive secretaries of the 
Oxford Junior Scientific Club. 

He was still working at crystals, and at the Royal 
Society s soiree in June had a fresh exhibit of models 
to illustrate the properties of quartz. 

He took little part that session in the work of 
the House of Lords, but paired in favour of the 
Bill for Legalizing Marriage with a Deceased Wife s 
Sister, and against the Tenants Arbitration Bill. 

In June the Ampere gold medal was awarded 1 
to Lord Kelvin by the Societe d Encouragement. 
This medal is awarded to the Frenchman or 
foreigner whose labours have had the greatest in 
fluence, during the six preceding years, on the 
progress of French industry. 

Von Helmholtz, who, in the previous autumn, 
had had a severe fall, became seriously ill in the 
summer of 1894, and Lord Kelvin wrote : 

July 6/94. 

MY DEAR MRS. HELMHOLTZ We are much dis 
tressed to see in to-day s papers that your husband, my 
old friend, has been taken ill. I hope very much that 
the illness is not so severe as may have been apprehended. 
It will be very kind if you will write and tell me of him. 

You must give him my most affectionate messages 
and warm sympathy. We shall be very anxious to hear 
what you can tell us. 

1 The terms of the award refer to the Atlantic cable work and to his 
union of practical engineering with mathematical power. " He has been 
the educator of our time. He has renewed theories, transformed scientific 
methods, opened out unforeseen paths, provoked the adoption of a logical 
system of units and measures, and contributed in an incalculable sense to the 
progress of industrial electricity." 


Lady Kelvin sends her love, and I remain, dear Mrs. 
Helmholtz, yours most truly, KELVIN. 

P.S. It happens that at this moment I am engaged 
with a problem that he started 47 years ago, the oscil 
latory discharge of a Leyden jar. 

The British Association meeting of August 1 894, 
at Oxford, was made notable by two events : the 
announcement of the discovery of argon by Lord 
Rayleigh and his coadjutor Professor (now Sir 
William) Ramsay, and the sending of wireless 
signals between the Clarendon laboratory and the 
Museum by Professor (now Sir Oliver) Lodge by 
means of Hertzian waves received by coherer and 
tapper. Lord Kelvin read a paper on hydrodynamics, 
and two others on electrical experiments made in 
his laboratory. There was a discussion also on 
Maxim s flying machine, which Lord Kelvin (who 
had himself in July had the opportunity of taking a 
"flight" in it) described as a "kind of child s per 
ambulator with a sunshade magnified eight times." 
He did not believe in the aeroplane, and thought 
the problem of flight might be better solved with a 
platform having a vertically working propeller at 
each corner : an aeroplane was like an eagle which 
had to take a run before it could rise. 

After leaving Oxford, Lord and Lady Kelvin 
went abroad. Lady Kelvin stayed at Aix, while 
Lord Kelvin took a cruise on the s.s. Electra, in 
the Mediterranean, visiting Syra, Constantinople, 
Sevastopol, Odessa, Athens, Corinth, and Genoa, 
back to Aix returning to Netherhall in the middle 

VOL. II 2 A 


of September to spend the autumn in quiet enjoy 
ment of his home. 

With the death of von Helmholtz, on September 
8th, 1894, Lord Kelvin lost one of his oldest and 
most-cherished friends. 

PARIS, Oct. ii, 1894. 

came to us here yesterday evening, and we sent a tele 
gram to tell you of our sympathy with you in this great 
grief. Your letter to Lady Kelvin, which she forwarded 
to me while I was still away on my cruise, made me very 
anxious, but I still hoped to hear of recovery and to be 
able to look forward to other happy meetings with my 
friend. But it was not to be. 

I am full of recollections of happy meetings in the 
past, of which the first was when he came to see me at 
Creuznach in 1856, and all of which were to me un 
alloyed pleasure. The loss to myself is so severe that I 
cannot speak of it, and I feel that I must not intrude on 
your own most sacred sorrow. But I feel that I must 
write this now on our way home to Largs, to tell you 
of my heartfelt grief, and to express for my wife her 
deepest and warmest sympathy with you. Believe me, 
dear Mrs. von Helmholtz, ever your affectionate friend, 


Oct. 12/94. 

DEAR MRS. HELMHOLTZ I have been most deeply 
touched by your kind letter which I received a fortnight 
ago, with all that it tells me of my friend who is gone 
from us, and of his feeling for me. To know from you 
that the sympathy and loving friendship which grew in 
me from my admiration of his work before I had seen 
him, in those early times in Creuznach, and Bonn, and 
Arran, when we were together, has been so perfectly 
reciprocated by him, is to me not only a pride and 
honour, but a happy possession. 


When the grief is so fresh I feel that it is almost 
cruel to speak of happiness. But even the grief, never 
to be lost, is brightened, not diminished, by the recollec 
tions of his life, and the knowledge of how beautifully 
and perfectly it worked for good and happiness. And 
believe me, it will be for all your life a happiness to 
know how his time in this world has been spent, and how 
much his memory is valued in his own country, and by 
all the scientific people of the whole world. 

We shall be much interested to hear what you resolve 
about a house. If one can be found near Ellen I am 
sure you will like to be near her and your grandchildren. 
We shall be much pleased to have one of the reproduc 
tions from Lembach s portrait if you find that you can 
have it done satisfactorily. 

Lady Kelvin sends her kindest love, and I remain, 
yours always affectionately, KELVIN. 

To Lord Kelvin, as President of the Royal 
Society, fell the duty, at the annual meeting on 
November 30, 1894, of recording the deaths of 
several celebrated Fellows, including Tyndall and 
Helmholtz. Of both he spoke with sympathy none 
the less sincere because brief. Then he turned 
to enumerate the -scientific triumphs of the year, 
chiefest among them the discovery of argon. 

Rayleigh, persevering in the main object which he had 
promised in 1882, "a redetermination of the densities of the 
principal gases," attacked nitrogen resolutely and, stimulated by 
most disturbing and unexpected difficulties in the way of obtain 
ing concordant results for the density of this gas as obtained 
from different sources, discovered that the gas left by taking 
vapour of water, carbonic acid, and oxygen from common air was 
denser 1 by ^^ than nitrogen obtained from chemical processes 
from nitric oxide, or from nitrous oxide, or from ammonium nitrite, 

1 "On an Anomaly encountered in Determinations of the Density of 
Nitrogen Gas," Roy. Soc. Proc., April 1894. 


thereby rendering it probable that atmospheric air is a mixture of 
nitrogen and a small proportion of some unknown and heavier 
gas. Rayleigh, and Ramsay, who happily joined in the work at 
this stage, have since succeeded in isolating the new gas, both 
by removing nitrogen from common air by Cavendish s old 
process of passing electric sparks through it, and taking away 
the nitrous compounds thus produced by alkaline liquor, and by 
absorption by metallic magnesium. Thus we have a fresh and 
most interesting verification of a statement which I took occasion 
to make in my Presidential Address to the British Association in 
1871 r 1 "Accurate and minute measurement seems to the non- 
scientific imagination a less lofty and dignified work than looking 
for something new. But nearly all the grandest discoveries of 
science have been but the rewards of accurate measurement and 
patient, long-continued labour in the minute sifting of numerical 
results." . . . 

After the address came the presentation of 
medals ; and this year the Darwin medal was 
awarded to Huxley, the youngest of the three who 
had "kept the bridge" in defence of Darwin s 
Origin of Species. Lord Kelvin, in handing the 
medal, made the following pronouncement : 

To the world at large, perhaps, Mr. Huxley s share in mould 
ing the thesis of " Natural Selection " was less well known than 
was his bold, unwearied exposition and defence of it after it had 
been made public ; and, indeed, a speculative trifler, revelling in 
problems of the "might have been," would find a congenial 
theme in the inquiry how soon what was now called " Darwinism " 
would have met with the acceptance with which it had met, and 
gained the power which it had gained, had it not been for the 
brilliant advocacy with which in its early days it was expounded 
to all classes of men. That advocacy had one striking mark : 
while it made, or strove to make, clear how deep the view went 
down and how far it reached, it never shrank from striving to 
make equally clear the limits beyond which it could not go. In 
these latter days there was fear lest the view, once new, but now 
familiar, might, through being stretched farther than it would 
bear, seem to lose some of its real worth. They might well be 
glad that the advocate of the "Origin of Species by Natural 

1 Republished in Vol. II. of Popular Lectures and Addresses, p. 156. 


Selection," who once bore down its foes, was still among them, 
ready, if need were, to " save it from its friends." 

The geological controversy (see p. 535) was 
reopened in January 1895, in Nature, by Professor 
John Perry, who pointed out that Lord Kelvin s 
estimate of 100 million years for the age of the 
earth, as deduced from thermal conductivity, must 
be increased if the rocks at higher temperature in 
the interior of the globe conduct better than those 
in the crust. If the conductivity is increased 
so that the temperature - gradient is i centi 
grade in 45 feet, instead of in 90 feet, the age is 
lengthened two hundred and ninety times. Lord 
Kelvin, to whom the matter had been privately 
submitted, wrote to Perry on December 13, 
1894, asking further data about conductivity, and 
adding : 

The subject is intensely interesting ; in fact, I would 
rather know the date of the Consistentior Status than of 
the Norman Conquest ; but it can bring no comfort in 
respect to demand for time in Palaeontological Geology. 
Helmholtz, Newcomb, and another are inexorable in re 
fusing sunlight for more than a score or a very few scores 
of million years of past time (see Popular Lectures and 
Addresses, vol. i. p. 397). 

So far as underground heat alone is concerned you 
are quite right that my estimate was 100 millions, 
and please remark (P. L. and A. vol. ii. p. 87) that 
that is all Geikie wants ; but I should be exceedingly 
frightened to meet him now with only 20 million in my 

And, lastly, don t despise secular diminution of the 
earth s moment of momentum. The thing is too obvious 
to every one who understands dynamics. 


He wrote to M. Mascart : 

Feb. 2, 1895. 

DEAR MASCART I have been looking back to my 
old estimate of the time which must have passed since 
the consolidation of the earth supposed to have been 
previously melted rock, and trying to find closer limits 
founded on definite information, if it is to be got, as to 
the following qualities : 

1. The melting temperature of rock of any time or 
lava under ordinary atmospheric pressure ; 

2. The thermal capacity of rock at different tempera 
tures up to melting ; 

3. The thermal conductivity, do., do., do., do.; 

4. The change of volume of rock on melting, do. 

I have been looking in all the text-books and books 
of tables in vain for such information. 

Has not Deville given really trustworthy measure 
ments of high temperatures, including melting points of 
glasses and stones ; and as to (4) also ? Moissan too 
has been working at high temperatures, and probably has 
results as to several of those four questions. You are 
sure to know, if any one knows, where information can 
be had from any part of the world (Italian observers of 
lava on Vesuvius ? American or others on the lava lake 
of Hawaii ?), and I should be greatly obliged by a few 
lines from you to tell me if you have of your own know 
ledge some of the information I want, or where I might 
be able to find it. 

The mathematical problem of finding the proper case 
of solution of the equation 

d fKdv\ dv 
dx\dx~) = ~dt 

with K and C given functions of v, is, I find, quite doable 
and very interesting. Yours always truly, 



February 4, 1895. 

DEAR MASCART Since my arrival home I have 
found, in the following papers, Philosophical Magazine, 
Oct. 1891, p. 353, Messrs W. C. Roberts-Austen and 
A. W. Rucker, " On the Specific Heat of Basalt " ; (2) Phil. 
Mag., July 1892, March 1893 (p. I and p. 296), Carl 
Barus, "On the Fusion Constants of Igneous Rocks," a good 
deal of valuable information on the subject on which I 
wrote to you from the train on Saturday. I write just to 
save you the trouble of referring me to any of these papers, 
but I shall be very glad if you can give me other refer 
ences or information. Yours very truly, KELVIN. 

Two months later Lord Kelvin wrote to Nature 
(vol. li. p. 438), that R. Weber having made 
measurements on sandstone and slate, saw no reason 
to think that thermal conductivity increases with 
temperature ; and that his own experiments showed 
the conductivity to be less, not greater, at high 
temperature. He also referred to a paper of January 
1893, m tne American Journal of Science, by 
Clarence King, who, reasoning from thermal data 
supplied by Carl Barus, concludes: "We have no 
warrant for extending the earth s age beyond 24 
millions of years." On which Lord Kelvin remarked : 
" I am not led to differ much from his estimate of 
24 million years." 

The Duke of Argyll came to Glasgow on January 
15, 1895, to address the Liberal Unionist Associa 
tion at the City Hall, and stayed with Lord Kelvin 
in his University house. Lord Kelvin presided at 
the meeting, which was densely packed. The 
Duke, who was far from well, had only spoken for 


about fifteen minutes when he fainted, and the 
meeting was dismissed. He was removed to Lord 
Kelvin s house, and recovered with a few days rest. 
Lord Kelvin had to go to Crewe on the 22nd to 
present the prizes at the Mechanics Institute in 
that town. In replying to a vote of thanks he 
remarked on the new electrical development which 
was taking place in the railway works at Crewe, 
where cranes and drilling machines were now being 
worked by power supplied electrically through 
wires. He went on to consider the possibility of 
an electrical train being turned out at Crewe, 
remarking that although such a thing might not be 
probable, still neither Mr. Webb nor the North- 
Western Railway would be behind any one else 
in the event of the steam locomotive being super 
seded by electricity. Mr. Webb, who presided, 
thereupon rejoined that should his company order 
one of their trains to be run by electricity, he would 
undertake to complete it in two months. 

On the 3Oth of January Lord Kelvin was at 
Wolverhampton to open the electric lighting station, 
where he complimented Mr. Parker on the machine 
that had been constructed at his works for trans 
forming continuous currents. In the evening he was 
entertained at a banquet by the Wolverhampton 
Chamber of Commerce, and spoke on the progress of 
engineering from the time of the Pyramids to the 
modern steam-engine of to-day. 

There was one science, he said, which was most 
fascinating, which until recent times was purely scientific, 


a subject for scientific investigation the science of elec 
tricity. But its application to practical uses had grown 
up wholly within the present century. A little before the 
middle of this century Faraday brought out his great dis 
covery, and in his own modest way anticipated some of 
the great success which followed. He virtually gave us the 
dynamo. The first practical application of electricity was 
to electrometallurgy. It was with reference to electricity 
for electroplating as well as for lighthouses that Faraday 
had said : " I gave you this machine as an infant ; you 
bring it back as a giant." They had seen it realized in 
Wolverhampton that day. 

The next day Lord Kelvin presided at the 
special meeting of the Royal Society called to 
hear a discussion of the discovery of argon by 
Rayleigh and Ramsay. The day after, he was in 
Cambridge attending the funeral of his old friend 
Professor Cayley. 

Lord Kelvin had now entered on the fifth year 
of his Presidency of the Royal Society. At the 
end of February 1895 ne wrote to Professor (now 
Sir Arthur) Rlicker, a Member of the Council : 

Another thing I wanted to speak to you about, if I 
had had the opportunity at our last Council meeting, is 
the next election to the Presidency. I shall have had my 
five years, and it will then be time to choose my successor. 
It has been a great pleasure to me to be President, but 
for many reasons I feel that however kindly the Council 
might feel in respect to re-electing me a sixth time (as 
indeed has been suggested to me as an idea that might 
possibly be entertained), it would be in all respects better 
that another should be elected. I should be glad, there 
fore, if members of Council would be considering in good 
time the question of who is to be elected. 

Then there were more Unionist meetings to 


attend, and papers to be read in Glasgow and 
London on the Dis-electrification of Air and on the 
Thermal Conductivity of Rocks. 

June and July brought the round of society 
dinners, and then he fled to Aix-les-Bains for rest 
and change. 

Lord Kelvin s Popular Lectures had been com 
pleted in 1894 by the belated publication of volume ii. 
on "Geology and General Physics," and a second 
edition of volume i. was called for. He sent a copy 
to Professor Tait, asking him for criticisms, and 
received a sheet bubbling over with incoherent fun 
couched in the old fantastic phrases, and furious com 
ments like those so freely bandied between the two 
friends in their earlier intimacy of the sixties, 
when the great Treatise was in the making. Lord 
Kelvin returned Tait s sheet scored over with lively 
rejoinders in blue pencil, and Tait posted it after 
him to Aix with repartees in red. The following 
letter is couched in less exuberant terms : 

July 2, 1895. 

DEAR TAIT I thank you heartily and without reserve 
of any percentage for all the corrections and ameliorations 
which you have given me for volume i., my chief motive 
for doing so being that I want you now, without any 
delay, to do likewise for volumes ii. and iii. Don t waste 
your time in trying to mitigate in any way your expression 
of disapprobation, however extreme. However keenly or 
even wildly you may express yourself I shall not be angry, 
not even sorry, except when I feel that the condemnation 
is merited. 

What you say as to Heat, a Mode of Motion, Elas 
ticity, a Mode of Motion, the title of Tyndall s beautiful 



book, and the nature of the Royal Institution Friday 
evening audience (which always includes such people as 
Stokes, Rayleigh, Schuster, Dewar, Lord Rosse, and all 
the best and strongest scientists who chance to be in 
London at the time with no more amusing evening engage 
ment to keep them away) does not pain me at all. " My 
withers are unwrung." So they are in respect to " centri 
fugal force." 

I accept " Scottish-built," but it must be kept for 
3rd edition. As to page 338, 1. 3, you will see that I 
have yielded. But in doing so I have spoiled my sentence, 
which was quite correct as it stood. Putting them together, 
with one part turned through zero angle relatively to the 
other, is much more ingenious than the choice of any other 
angle would have been. 

We (Gray ii. and I) have been making history here 
(? more important than that made by Mr. Brodrick and 
Campbell-Bannerman in another place) during the last 
i o days. We have done graphic histories of 22 encounters 
between a free particle (Boscovich) and a vibrator with 
from one to four impacts in each encounter. We are 
nearing to-day a test of the Maxwell-Boltzmann law of 
distribution of energy. Yours, K. 

From Aix-les-Bains Lord and Lady Kelvin took 
a short trip to Switzerland, returning in time for 
the British Association meeting at Ipswich on 
September n. Then a full month was spent at 
Netherhall. He was much occupied with calcula 
tions about the new Pacific Cable. 

In October 1895 tne Institut of France celebrated 
the centenary of its creation. Lord Kelvin, as one 
of the foreign associates, was invited to take part in 
the four days celebration. It began on October 23, 
with a religious service in the church of Saint 
Germain des Pre"s, followed by a greeting of the 


members to the foreign associates and corre 
spondents, and a formal reception by the Minister 
of Public Instruction, M. Poincare. The great day 
was the 24th, beginning with a meeting in the great 
hemicycle of the Sorbonne, at which the President 
of the Republic, M. Felix Faure, was present, and 
an oration was made by M. Jules Simon, and 
speeches by M. Ambroise Thomas and M. Poincare". 
In the afternoon there was a reception at the 
Elysee ; in the evening a grand banquet at the 
Hdtel Continental, at which Max-Muller was the 
spokesman of the foreign associates and corre 
spondents. Later, Lord Kelvin presented an address 
from the Royal Society, and in reply to an allocution 
of the President of the Institut, pronounced the 
following speech : 

Personnellement les mots me font defaut pour dire 
combien j apprcie le grand honneur que vous m avez 
confer^, d etre Associe" de 1 Institut de France. Mais je 
dois a la France une dette encore plus grande. Elle est 
vraiment YAlma mater de ma jeunesse- scientifique, et 
I inspiratrice de 1 admiration pour la beaut de la science 
qui m a enchaine et guide pendant toute ma carriere. 

Dans la bibliotheque du roi, pendant l e"t de 1839, j ai 
fait la connaissance d une petite partie de la Mecanique 
celeste de Laplace, pour un Essai sur la figure de la Terre, 
qu il m a fallu e"crire pour l Universit de Glascou, comme 
exercice d e"tudiant Avant que je quittasse 1 Universite 
de Glascou, mes professeurs m y avaient montr la splen- 
deur de Fourier. 

Six ans plus tard, le venerable Biot m a pris par la 
main et m a plac dans la laboratoire du College de 
France sous la direction de Regnault ; ainsi j ai vu ce grand 
physicien, de jour en jour, travaillant sur les proprites 


physiques des gaz. A Regnault et a Liouville je serai 
eternellement reconnaissant pour la bonte qu ils m ont 
temoigne e, et pour les methodes qu ils m ont enseigne"es 
sur la physique experimentale et mathematique dans Tan 

Un an plus tard encore, la Puissance motrice du feu, 
le travail de rimmortel Sadi Carnot, m a revele les 
rsultats si pratiques et si profondement ultra-theoriques 
de son genie penetrant. 

Ainsi j ai te nourri de la science la plus solide et vous 
comprendrez, mes chers Confreres, pourquoi je regarde, 
avec une reconnaissance profonde, la France comme mon 
Alma mater de science. 

Monsieur le President de 1 Institut et chers Confreres, 
je vous remercie de tout mon cceur de votre bonte pour 
moi, et pour Fhonneur que vous m avez fait en m appelant 
a repondre au nom de la Societe* Royale. 

The fetes concluded with a performance of Le 
Cid, at the Theatre Frangais, and a visit to 
Chantilly, where the aged Due d Aumale still 

Lord Kelvin hurried back to Glasgow for the 
duties of his Chair, but was interrupted by pro 
fessional work. A letter to Mrs. King on November 
13, from the Athenaeum Club, tells her that he will 
come to see her about 7 o clock that evening. 

I should have to leave at 9, as I am very busy with a 
law case * (bicycle tyres), for which I shall be all day in 

1 The case, relating to the < Clincher " tyre, lasted several days, and was 
heard by a learned Judge who was as guiltless as Lord Kelvin of having ever 
learned to ride a bicycle. After hearing his evidence the Judge turned to him 
and said : "Lord Kelvin, I have heard a great deal in this case about the 
tendency of the tyre to come out of the rim ; now, in this patent the inner tube is 
canvas-covered and inexpansible, and the pressure on the road tends to press 
the tyre into the rim." The answer came solemnly and with great delibera 
tion : "Suppose, my Lord, that I were riding a bicycle" (with the chief 
accent on the second syllable) "at a high velocity, and suppose that in order 


Court, and I shall have a good deal to write and work out 
for it here in the evening. It is a very interesting case 
and I shall tell you all about it. 

On November 27 Lord Kelvin presided at the 
Huxley Memorial Committee. On the 28th he 
was spokesman at a deputation to the Duke of 
Devonshire on behalf of the movement for a 
Teaching University for London. 

On the 3<Dth was the anniversary meeting of the 
Royal Society. Lord Kelvin s Address opened 
with an enumeration of the names of those Fellows 
who had died within the year including Cayley, 1 
Neumann, Huxley, 2 and Pasteur. He then spoke of 
the great catalogue of scientific papers undertaken 
by the Royal Society ; of the centenary of the 
Institut ; of the Challenger Expedition publications ; 
and of the discovery of argon and helium. Amongst 
the medallists of the year to whom he handed the 
medals were his former assistant Professor Ewing, 
and Professor (now Sir William) Ramsay, at one 
time a student in his laboratory. The following 

to decrease the velocity very quickly, I were suddenly to turn the front wheel 
so that its plane was substantially at right angles to the direction of motion, I 
think that there would be a tendency for the tyre to come out of the 
rim ! " 

1 In his reference to Cayley there is a personal note that cannot be omitted 
here : 

" In Cayley we have lost one of the makers of mathematics, a poet in the 
true sense of the word, who made real for the world the ideas which his ever- 
fertile imagination created for himself. He was the Senior Wrangler of my 
freshman s year at Cambridge, and I well remember to this day the admira 
tion and awe with which, before the end of my first term, just fifty-four years 
ago, I had learned to regard his mathematical powers. When a little later I 
attained to the honour of knowing him personally, the awe was evaporated 
by the sunshine of his genial kindness ; the admiration has remained unabated 
to this day, and his friendship has been one of the valued possessions of my 

2 See p. 1088 infra for a quotation from the appreciation of Huxley. 


are his closing words on vacating the presidential 
Chair : 

Five years have now passed since you elected me to be your 
President. Living at a distance of 400 miles from London, I 
felt that it could not be possible for me to accept the honour 
when the possibility of its being offered to me was first suggested. 
I accepted, with much misgiving as to my ability to perform the 
duty which would fall upon me; and now, after having been 
re-elected four times, I feel that if the interests of the Society 
have not suffered under my presidency, it is chiefly because they 
have been so faithfully and unintermittently cared for and worked 
for by the other officers, the Treasurer and the Secretaries, who 
have left nothing undone that could be done to promote the 
welfare of the Royal Society. For their unfailing kindness to 
myself I can only offer my heartfelt thanks. I soon found that 
what I looked forward to with apprehension the Council meet 
ings, and as many of the ordinary meetings as I could attend, 
during my University session in Glasgow were the reverse of 
fatiguing ; and I am only sorry that I have been so many times 
obliged to forgo the pleasure of performing that part of my 
presidential duty. I look back otherwise with unmixed pleasure 
to all the meetings at which I have presided, and my sole regret 
now is I cannot disguise it, and it is a very keen regret that 
these five years are passed, and that to-day I cease to be your 
President. I thank you all, my colleagues of the Royal Society, 
for electing me five times to be your President, for forgiving me 
all my shortcomings, and for the inestimable benefit which you 
have conferred on me by giving me your friendship. 

The following letter to Lord Rayleigh brings us 
back to mundane affairs : 

Dec. 14/95, 

DEAR RAYLEIGH My secretary is busy drawing a 
new (old) form of water-tap, for which I am immediately 
going to take out a patent (to get over the possibility of 
failure in hard water such as we have in the Athenaeum, 
and in some other places in the south of England, in the 
existing pattern which has been bringing discredit on it, 
and which, since I ceased to be P.R.S., I saw to be due 
to geometrical and mechanical ill-conditionedness, pro 
ducing no bad result with Loch Katrine water), and this 


is my apology for less clear writing than you should 
otherwise have had respecting encounters. 

I think the post of scientific adviser to the Trinity 
House would be particularly interesting to you, and if you 
think the conditions as to duty expected and remunera 
tion are satisfactory, you would, I think, be quite right to 
accept it. Yours, KELVIN. 

He wrote on December 24 to Professor Hugh 
Blackburn : 

You were no doubt amused by letters of arm-chair 
enthusiasts for the beauties of Nature, about the Falls of 
Foyers, and (I hope) pleased by the final quietus to the 
fever given by the County Council. The turbines, I 
hope, will be going, and the aluminium coming, by 
February or March. 

Did you receive a Comptes Rendus containing my 
" allocution " at the centenary banquet in Paris ? If not, 
it will be sent. You will see that I did not forget 
Glasgow. I am not sure if 3 1 Rue Monsieur le Prince 
has not been taken down, to give space for new (Ecole 
de Medecine) buildings. 

The year closes with a letter to his niece, Miss 

May Crum : 

Christmas, 1895. 

MY DEAR MAY Your father brought me your letter, 
and we have been greatly enjoying his visit. It is very 
kind of you to console me on my sad imprisonment. 
Really I feel perfectly well, and strongly disposed to 
disagree with Dr. Tennent, but your Aunt Fanny won t 
allow me to disobey. It will be too sad if we lose the 
delightful time we had been looking forward to at 
Thornliebank, but I hope when the 3rd comes, or before 
it, we may find Dr. Tennent more reasonable. ... I 
have been reading Lucretius, much helped by Munro s 



(not the author of THE doctrine) translation, and trying- 
hard on my own account to make something of the clash 
of atoms, but with little success. Your affectionate 
unk(! !)le, KELVIN. 

The year 1896, which was to witness the jubilee 
of Lord Kelvin s tenure of the Chair of Natural 
Philosophy, opened inauspiciously enough, for he 
was far from well that winter. All through 
December 1895 he complained at intervals of a 
tired leg, sore and painful at times, but just before 
Christmas, when he was purposing to leave Glasgow 
for Netherhall, an cedematous swelling, such as 
had troubled him much after the accident of 1861, 
caused his medical adviser to order him to keep 
his bed for several weeks. At the end of January 
there supervened a sharp attack of pleurisy. Though 
suffering much he bore his sufferings with great 
patience, and was greatly helped by his ability to 
sleep soundly. Except when the pleurisy was acute 
he worked at his notebook, dictated letters to his 
secretary, and took the keenest interest in the 
events of the hour, both scientific and political, as 
the following letters show. It had been settled 
that he was to give another Friday evening dis 
course at the Royal Institution in April, but he now 
wrote to the Honorary Secretary, on the loth of 
January, that he must abandon the project : 

I have been almost wholly confined to bed since the 

1 6th of December on account of a swelling in my bad 

leg, which was broken Christmas eve 35 years ago. I 

am now much better, but the doctor s orders are most 

VOL. II 2 B 


peremptory that I am still to keep, very much at least, 
to the sofa, and as much as possible avoid standing. I 
need not tell you that I am exceedingly sorry to fail you 
for the Friday evening lecture to which I had been 
looking forward with much pleasure. 

Eventually M. Lippmann took Lord Kelvin s 
place, and lectured on Colour Photography. 

The papers had been full of the wonders of 
Rontgen s rays, about which Lord Kelvin was 
intensely sceptical until Rontgen himself sent him 
a copy of his Memoir, 1 whereupon he wrote : 

January 17, 1896. 

DEAR PROF. RONTGEN When I wrote to you thank 
ing you for your kindness in sending me your paper and 
the photographs which accompanied it, I had only seen 
the photographs and had not had time to read the paper. 
I need not tell you that when I read the paper I was 
very much astonished and delighted. I can say no more 
now than to congratulate you warmly on the great dis 
covery you have made, and to renew my thanks to you 
for your kindness in so early sending me your paper and 
the photographs. Believe me, yours very truly, 


He wrote to Sir Joseph (now Lord) Lister on 
January 27 : 

Ask Rayleigh if he is not in a state of great excite 
ment about Rontgen s X-rays. 

To his sister, Mrs. King, now in her seventy- 
seventh year, he wrote : 

1 W. C. Rontgen, Ueber eine neue Art von Strahlen, Sitzungsber. der 
Wiirzburger Physik-medic. Gesellschaft, December 1895. 


Sunday, Jan . 26/96. 

MY DEAR ELIZABETH I am very sorry to have so 
long been prevented from writing to thank you for the 
lovely new year s gift (I can t look at it and see it as only 
a new year s card) which Fanny brought to me from you 
when we were in London. Since our return I have had 
my secretary at work with me from instantly after break 
fast (sometimes even before it was finished) till 7.45 or 8 
in the evening, every day except yesterday, when I 
managed to get him away by 2.30 for a Saturday after 
noon walk which he told me he was to have with a friend 
(this sort of thing will become illegal, I am afraid, when 
the 8 hours bill becomes law). So you will understand 
why it is that I have so long been kept from writing 
to you. 

Fanny and I both think the picture quite lovely and 
very interesting, with the old tower overgrown with hang 
ing creepers, and the ruined village, and the dome of 
St. Peter s in the distance. We are going to have it 
framed and hung up where we shall see it. 

I am still ordered to keep the bad leg up and give it 
all the rest possible, and told emphatically that the more 
thoroughly I obey this order the sooner I shall be quite 
well and again ready for everything. I believe I am (I 
mean the leg is) really somewhat better, but the progress 
is disappointingly slow. I am feeling perfectly well, and 
am getting on with my work (with secretary s aid), as well 
as staying in bed till lunch-time, and as nearly as possible 
in the same position till night downstairs allows, but it 
is tiresome and disappointing to be so long kept from 
walking about, and going to the laboratory for my work 
there which is always going on, etc. etc. 

I am afraid this is rather queer writing, as it is done 
on a table in bed ! Newspaper reading has been very 
exacting of late. What inconceivable folly (not to use a 
harsher word) Dr. Jamieson s bringing those 700 or 800 
young men to what they came to seems to have been. 
It is inconceivable also how officers of the British Army 


joined in the mad affair. What a trial and investigation 
there must be ! One thing must follow, that our Govern 
ment must never again shirk their duty of governing and 
hand it over to irresponsible, unqualified people or com 
panies. Your aff. brother, KELVIN. 

P.S. I hope you and Elizabeth, Jun r ., are both much 
better than when Fanny saw you, and that Agnes is 
keeping well. 

He sent Stokes on February i a long mathe 
matical letter, ending thus : 

In respect of the Rb ntgen X-rays, are you a longi- 
tudinalist, or an ultra-violetist, or a tertium-quidist ? . . . 
I had a slight attack of pleurisy, which came on suddenly 
on Monday. I am feeling much better now, and the 
doctor is well satisfied with progress, but he won t let me 
out of his hands on any account yet, and I don t know 
what he will say when he hears that I have been dictating 
this, also a short article for Natiire on " Maxwell s Infinite 
Velocity for the Propagation of Electrostatic Force," for 
which look out next week. 

A letter on Rontgen s rays to Oliver Lodge, 
of February 4, is printed in another connexion on 
p. 1062. 

On February 10 Lady Kelvin sent word to 
Mrs. King that Lord Kelvin was going on as well 
as possible, but that she feared the leg was going to 
tie him down for some time : 

The doctors all insist on the necessity of absolute rest 
Even Sir Joseph Lister, who wrote to Dr. Hector Cameron 
to ask him to see Dr. Tennent, writes begging him, how 
ever well he feels, to keep quiet and rest. The remains 
of pleurisy is keeping him still in bed at present, and the 
leg is still swelled a good deal. Dr. Tennent always ends 



up by saying he will be quite well for his jubilee. It is 
fortunate that James [Bottomley] is so well, for he is 
obliged to take all William s lectures. William frets very 
much at not being able to take his lectures. He has had 
the higher mathematicians twice in the dining-room. . . . 
He is allowed to do some work, fortunately. 

Again he wrote to Stokes, and to Admiral 
Wharton, and to Professor (now Sir) Joseph J. 
Thomson : 

February 12, 1896. 

DEAR STOKES I am very much obliged to you for 
your letter of yesterday. Rayleigh gives me a reference 
to 301 of his book on Sound, volume ii., where there is, 
particularly in equation (12), something for condensational- 
rarefactional waves, analogous to what I wrote to you 
regarding transverse vibrations in an elastic solid in my 
letter of Feb. I. 

As to the true Kathodenstrom, it is wonderful how the 
Germans have called it Kathodenstrahl, having allowed 
themselves to be misled by Hittorf and Goldstein. They, 
every one of them that I know of, except Helmholtz, have 
insisted with something like strong partisan spirit upon a 
ray of undulatory light from the cathode, and have blindly 
refused to accept Varley s conclusion of a torrent of mole 
cules, corroborated as it is by Crookes. I enclose a 
marked copy of my address of 1893, which may show 
you, or remind you of some dates and references on the 

As to the Rontgen rays, you will see in Nature for 
Jan. 23, page 275, second column, that Rontgen himself 
made the experiment which you tell me J. J. Thomson 
thinks of making, and that he found, as nearly as he could 
test it, an intensity varying inversely as the square of 
the distance. This, of course, if confirmed, is decisive 
against the hypothesis of " push " in an incompressible 

I feel strongly disposed to Rontgen s own supposition 


of condensational - rarefactional waves, but still I see 
tremendous difficulties. 

Thanks for your inquiries. I am now practically well 
except that the doctor still rigorously orders the leg to 
be kept horizontal, and so for the present I am kept in 
bed. The pleurisy is nearly quite gone away. Yours 
always, KELVIN. 

February 12, 1896. 

DEAR WHARTON I am very glad to have the paper 
which you send me with your letter of yesterday. I shall 
read it with great interest. I have no doubt that you 
are right that the prime motor of surface currents is the 
wind. If you care to look at page 145 of Volume III. of 
my Popular Lectures and Addresses, you will see something 
on the subject which I hope you will find correct. There 
certainly is a tremendous shovelling, as it were, of water 
to leeward in breaking waves under strong wind, and I 
suppose every gale of wind, lasting for two or three days, 
leaves a strong surface current for several days after it. 

There certainly are also deep - seated permanent 
currents, due to differences in temperature in the water 
itself, by which great changes of water, especially between 
polar and equatorial regions, are produced. There was a 
great deal that was right in Dr. Carpenter s views on this 
subject, though I believe he did not sufficiently take also 
into account the great and rapid surface currents produced 
by wind, and the widespread distant return surface cur 
rents which they entail, as in Clayden s model which you 

I suppose I am right in believing that nowhere, either 
in Antarctic regions or in North Polar regions, is there 
any great area of ice-bound sea which is not landlocked ? 
I should be greatly obliged by a single line in answer to 
this. Yours truly, KELVIN. 

February 18, 1896. 

DEAR THOMSON I am exceedingly interested in 
three things you tell me in your letter of the i6th, and 
much obliged to you for telling me them. 


1. The selective absorption of some of the Rontgen 
light which you find with plates of the same metal, but of 
different thicknesses, seems almost certainly to be precisely 
analogous to the absorption of ordinary light by coloured 
glass, and therefore to prove that you have got different 
colours of Rontgen light. If this is true, you will of course 
find the different kinds of the light that you get by your 
sifting through plates of different metals, will, all of them, 
follow the law of inverse square of the distance, except in 
so far as some of them may be sensibly absorbed by a 
metre or two of air. It is most interesting to think that 
now in metals you have quasi-coloured glasses for Rontgen 
light, and that dielectrics are nearly white, beside being, 
as Rontgen found them, wonderfully transparent. One of 
the next things to try is the relative photographic powers 
of the different colours of the Rontgen light, and to test 
different photographic substances so as to find which is 
most sensitive for one colour and which for another ; l also 
similar experiments with different phosphorescent sub 
stances. It remains to be seen, too, whether the different 
colours of the X-light have not different refractive indices, 
if any one of them has really a refractive index sensibly 
different from unity. I enclose a paper of Lenard s, as it 
may save you the trouble of looking it up in Wiedemann, 
if you have not seen it already. I have not had time 
yet to read it through. You may perhaps find in it some 
thing of the coloured-glass principle proved in numerical 
results, though not referred to in the text. 

2. It is most interesting to find the X-light causing 
the air to be temporarily electrolytic. I suppose this has 
already been done for the ultra-violet light. We have 
done it for flame here, as you will see from one of the 
enclosed papers. Fumes from a spirit-lamp flame, passing 
between plates of polished zinc and polished copper (the 
flame being about a foot below the plates), produce a 
difference of potentials equal to -78 of a volt between 
copper wires connected to the two plates. This is just 

1 It seems quite improbable that the best photographic substance for 
sensibility for X-light has been found by any one hitherto. 


about the same as is produced by a bridge of pure 
water between the polished plates. 

I enclose also another paper (by Maclean and Goto) 
related to this subject, which has only been published in 
the Proceedings of the Glasgow Philosophical Society. 

3. Quite wonderful * and most interesting ! Was the 
saturated steel needle the test ; or was something else 
used, more adapted for receiving a succession of signals ? 
Yours very truly, KELVIN. 

The next letter gives Lord Kelvin s reasons for 
the preference he had long held for the use of con 
tinuous currents in electric transmission of power : 

February 25, 1896. 

that I am confined to bed (and to be so according to 
doctor s orders for a fortnight), I should have been happy 
to see you, and I should certainly have been greatly pleased 
and interested to talk over with you the subject of your 
letter which I have received this morning. 

For electric transmission of power over very long 
distances, very high pressure is necessary for economy. I 
object to the use of alternate currents for this practical pur 
pose, primarily because 41 per cent higher pressure can be 
transmitted to a great distance by direct current than by 
alternate current, with the same conductors and insulation 
in the two cases. For distances exceeding 50 miles it 
would probably be advisable to use two wires, one of them 
at + 20,000, and the other at 20,000 volts difference 
of potentials from the earth. I believe it would not be 
possible to obtain, for such distances, as good economy 
by alternate current as by direct current. The prime cost 
of direct -current dynamos for such purposes has never 
been gone into practically. 

Let me know if there is any other question that I can 

1 [This refers to Rutherford s "magnetic detector," with which he had 
been sending wireless signals by means of Hertz waves to a distance of half 
a mile across the town of Cambridge.] 




answer in writing. Should you think it worth while to 
come here and talk the matter over with me, I should be 
delighted to see you and to discuss all the pros and 

I thank you for your kind inquiries. I am much 
better, and I am really feeling perfectly well, but medical 
opinion is quite decided that absolute rest for some weeks 
yet is necessary for my leg. They say that if I am 
thoroughly obedient to them in this respect I will be 
perfectly well. This is satisfactory, but I am disappointed 
to be kept laid up so long. Believe me, yours very truly, 


Lady Kelvin was able by the end of February to 
write to Mrs. King: " William is really very well 
in his bed, and very busy. The days are never 
long enough for all he wishes to do ! " Many 
were the letters he wrote to Stokes and to Lord 
Rayleigh, discussing keenly the possible explana 
tion of Rontgen s rays. Acknowledging one from 
Stokes on phosphorescence, he wrote on March 27, 

I have instructed the Pitt Press to send you advance 
corrected proofs (which have been in print eight years) of 
the first 112 pages of my Baltimore Lectures. You will 
find the formula I gave you a few weeks ago on page 106, 
also a good deal of fluorescence and phosphorescence 
jangling about in one-half or other of most of the lectures. 
I am afraid you will be very much shocked to see such a 
rigmarole as having been given in University Lectures. 
I hope it will not plague you to have them in your hands 
and to keep them till you get the rest of the volume from 
the Pitt Press, which I hope may be within a year from 


In April and May Lord Kelvin was in London, 
and gave evidence before the Select Committee on 


Petroleum. The Act of 1871 had required that 
paraffin oil should fulfil a flash-test of 100, but in 
1879 the Home Office had lowered the test to 73, 
thereby admitting the free sale of dangerous low 
flash-point oils. Lord Kelvin told the Committee : 

The principle of safety is that oil should never in a lamp reach 
the temperature of the close-test flash-point. I advise the Com 
mittee to fix a flash-point which shall be higher than oil is likely 
to reach under ordinary conditions of ordinary use. 

I am clearly of opinion that in order to avoid accidents the 
flash-point must be raised, and that no construction of lamp will 
meet this difficulty. 

I call it terrible that 2 5 per cent of all the deaths by fire in 
London during the year were due to paraffin-lamp accidents. 

It seems to me that the logical outcome of Sir Frederick 
Abel s work ought to have been to declare that the 100 test in 
force in the 1871 Act must be fulfilled by a proper close test. 

There was no good reason for reducing the test from 100 to 
73. It seems to me that it was a mistake. 

I think that the accidents which have been reported are amply 
sufficient to justify prohibitive legislation amply sufficient. 

In spite of this, and similar views expressed by 
such chemists as Sir Henry Roscoe and Sir William 
Ramsay, nothing has been done. 

Lord Kelvin felt very strongly on this question. 
Formerly no paraffin oil was allowed to be sold 
unless it passed the flash-test at noF., that is to 
say, unless it was of such a quality that even when 
warmed to 1 10 it did not give off explosive vapours. 
The American oil-dealers in 1865-7 agitated to get 
this reduced to 100, although in British Govern 
ment offices no oil is accepted of lower flash-point 
than 105, and many of the American States insist 
on a test equally stringent. Yet in 1868 the test 
was lowered to 100, and an open test-cup was 


legalized, which in practice proved to be erroneous 
to an average extent of 27 degrees. In other words, 
oil which was actually giving off explosive vapour 
at 73 (Fahr.) did not flash in this open cup until it 
reached 100. The number of fires due to paraffin 
lamps increased owing to the introduction of cheap 
low-flash oils. In spite of this, in 1879, when a 
new and more efficient test was adopted, the flash 
point was by a scandalous manoeuvre reduced to 73. 
In the ten years from 1881 to 1891 the fires in 
London due to paraffin oil went up to 50 per cent. 
It was chiefly due to Lord Kelvin s evidence that 
the Select Committee rather reluctantly recom 
mended the raising of the flash-point (Abel test) to 
100. A Flash-point Bill, introduced in 1899, was 
defeated on second reading by 244 votes to 159, a 
result mainly brought about by the promise (un 
fulfilled) of Mr. Jesse Collings (the Under-Secretary 
for the Home Department) to bring in a Govern 
ment Bill to deal with the whole matter. A new 
Government came in in 1900, and another in 1906, 
but nothing has been done. The scandal of the 
free sale of dangerous low-flash oil continues. 



CELEBRATIONS of birthdays and jubilees of dis 
tinguished men are much less frequent in Great 
Britain than in most Continental states. But on 
rare occasions even the stolid Briton is stirred into 
a public demonstration of feelings that he is apt 
ordinarily to conceal. The Jubilee of Lord Kelvin, 
which was celebrated at Glasgow University on 
June 15, 1 6, and 17, 1896, was one of these rare 
occasions. His colleagues in the University, his 
students past and present, his fellow-workers in 
science and in University life, all united to make the 
event a memorable one. From the official record 
published by the University the following account 
is taken, with but few added details. 

It was because of the unique character of the 
work done and of the personality of the worker that 
the Jubilee of Lord Kelvin became one of the most 
strangely impressive functions. It had in it some 
thing of the nature of a spontaneous outburst of 
enthusiasm, as well as of the studied and respectful 
homage shown by representatives of all the world 
to a great thinker and actor. At the gatherings 



held in the University and in the City of Glasgow 
in 1896 to signalize the fiftieth year of Lord Kelvin s 
tenure of the chair of Natural Philosophy in the 
University of Glasgow, no element in our academic 
or natural life was left unrepresented. Delegates 
from every seat of learning and from nearly every 
scientific body in Great Britain and Ireland were 
assembled, and with them were the men who have 
made or are making their mark in Glasgow and in 
the West of Scotland. Representatives there were 
too from the Colonies, and many brilliant and dis 
tinguished foreigners came to do honour to their 
great scientific fellow-worker. 

The students at the University had invited 
delegates from the Universities of Great Britain 
and Ireland, and from many foreign Universities 
as well, and throughout the celebrations it was 
evident that the undergraduates were as eager to 
honour their senior professor as were his oldest 
friends. It was interesting also to notice that 
among the great number of congratulatory messages 
received by Lord Kelvin during this week, there 
were many from men who had formerly been under 
graduates in his class, and who were now occupying 
posts in various parts of the world. As an instance 
of this may be mentioned the addresses sent from 
former Japanese students of Lord Kelvin s class, 
now at Tokyo. 

The first gathering, a conversazione in the halls 
of the University, took place on the evening of 
Monday, June 15, 1896. 


It was a brilliant sight, and very different from 
the daily routine of academic life. The sombre 
halls and cloisters and staircases of the College 
were lit up by electric light, decorated with flowers, 
and filled with a moving mass of colour ; and the 
summer evening was so beautiful, that in the eastern 
quadrangle many of the guests strolled up and down 
listening to the pipes of the Gordon Highlanders. 
The innumerable differences in the robes worn 
by the guests represented well the cosmopolitan 
character of the gathering. 

About two thousand five hundred ladies and 
gentlemen had been invited, embracing the repre 
sentatives of Universities, Societies, and Institu 
tions, and other distinguished visitors ; the members 
of the University Court and Senate, about four 
hundred and fifty members of the General Council, 
and fully two hundred Students ; the Lord Provost, 
Magistrates, and members of the Town Council, 
and many prominent citizens of Glasgow and 
residents in the West of Scotland and other parts 
of the country. The Bute Hall, the Hunterian 
Museum, and the upper hall of the Library were 
thrown open, and in the latter there was an exhi 
bition of mechanical, electrical, and scientific 
apparatus and contrivances designed by Lord 
Kelvin ; and of the diplomas and certificates of 
membership, as well as medals, presented to him 
by Universities, Colleges, and Institutions. 

In the upper hall of the Library the Eastern, 
the Anglo-American, and the Commercial Cable 



Companies had fitted up siphon -recorders in con 
nection with their cables, and a large number of 
congratulatory telegrams 1 from all parts of the 
world were received in the course of the evening, 
and suitable replies transmitted. 

After the Conversazione the Students held a 
Gaudeamus and a reception of delegates from other 
Universities in the large hall of the Union. 

On Tuesday morning, June 16, 1896, an im 
pressive function took place in the Bute Hall 
of the University, when the many distinguished 
men assembled in Glasgow presented to Lord 
Kelvin addresses from the Universities and 
Societies whom they represented. A letter was 
first read from the Prince of Wales : 

\QthJune 1896. 

DEAR LORD KELVIN The Prince of Wales desires me to 
offer you his warmest congratulations upon your having attained 
the fiftieth year of the tenure of your professorship in the 
University of Glasgow. 

1 Amongst the telegrams received during the evening was one from the 
Glasgow Jubilee Committee which they sent from Glasgow by the Anglo- 
American Atlantic Cable to Newfoundland, thence via New York, Chicago, 
San Francisco, New Orleans, Washington and New York back through the 
cable to Lord Kelvin. It ran : 

" By the Atlantic cable, which represents your unrivalled combination of 
scientific genius and practical skill, the Glasgow Jubilee Committee send you 
their warmest congratulations." 

This message occupied seven and a half minutes in traversing the circuit 
of abou f 20,000 miles ; and to it Lord Kelvin replied in a message which 
took but tour minutes to compass the same route : 

" The cable companies have beaten Ariel by half a minute. Warmest 
thanks to the Glasgow University Jubilee Committee." 

The Viceroy of India telegraphed from Simla, the President of the 
Orange Free State from Bloemfontein, and Earl Grey from Bulawayo. 

Lord Glasgow telegraphed from New Zealand, and Sir James Sivewright 
from Cape Town. Congratulations were received from several prominent 
Americans, including Professor Elihu Thomson, Mr. Westinghouse, and Mr. 
C F. Brush. 


His Royal Highness is in most cordial sympathy with the 
eminent representatives of universities, learned societies, and 
other public bodies in different parts of this empire and in 
foreign states, who, to do you honour, have assembled in the 
University which has for a long series of years eventful 
through the rapid advance of science and its applications en 
joyed the high prestige derived from your close association with 
its work, and from the invaluable and brilliant contributions to 
science resulting from the researches carried on by you during 
the last half-century within its walls. 

The Prince of Wales remembers with much satisfaction that 
he had the gratification, seventeen years ago, to present you 
with the medal instituted by the Society of Arts as a memorial 
of the Prince Consort, and awarded to men who have rendered 
pre-eminent service in promoting arts, manufactures, and 

The work which you had at that time accomplished was 
but an earnest of the important researches to which you have 
since then devoted yourself so indefatigably, and he cherishes 
the sincere hope that you may long continue to enjoy the 
happiness derived from the most gratifying evidence that the 
high value of the service rendered by you through science to 
mankind is universally recognised and appreciated. I remain, 
dear Lord Kelvin, yours truly, FRANCIS KNOLLYS. 

P.S. His Royal Highness desires me to repeat what he 
has already stated to the University authorities, how greatly he 
regrets that long-formed engagements in the south prevent him 
from having the pleasure of being present on the occasion of 
this interesting celebration. FRANCIS KNOLLYS. 

Thereafter the following Congratulatory Ad 
dresses were presented to Lord Kelvin by the 
following representatives : 


Aberdeen, Professor Finlay, M.D., Professor Niven, F.R.S., 
and Professor Pirie ; Ann Arbor, Professor R. M. Wenley, M. A., 
D.Sc., D.Phil. ; Baltimore (Johns Hopkins University), James 
A. Thomas, M.D. ; Bombay, Mr. Justice Jardine, Vice- 
Chancellor, and G. N. Nadkarin, LL.B. ; Cambridge, Professor 
A. R. Forsyth, Sc.D., F.R.S., Professor Sir George G. Stokes, 



LL.D., D.C.L., F.R.S., and Professor J. J. Thomson, M.A., 
F.R.S. ; Edinburgh, Professor Crum Brown, M.D., F.R.S., and 
Professor Sir William Turner, LL.D., D.C.L., F.R.S. ; Glasgow 
(Senatus Academicus}, Professor Stewart, D.D. ; Glasgow 
University (General Council), John G. Kerr, M.A., and Archibald 
Craig, LL.B. ; Heidelberg, Professor Quincke; Kasan\ Lille, 
Professors Pinloche and Angellier ; London, Sir Henry E. 
Roscoe, F.R.S., Vice-Chancellor, and Professor Carey Foster, 
F.R.S. ; Montreal (M { Gill University), Sir D. A. Smith, G.C.M.G., 
LL.D., Chancellor, and W. Peterson, LL.D., Principal; New 
Haven (Yale University]; New York (Columbia University], 
Professor Van Amringe ; Oxford, Professor Clifton, F.R.S., the 
Provost of Oriel, and Professor Burdon Sanderson, F.R.S. ; 
Paris, Professor Bonet-Maury ; Philadelphia, Professor G. F. 
Barker, M.D. ; Princeton, Professor Woodrow Wilson ; Rome, 
General Annibale Ferrero ; St. Andrews, Professor Pettigrew, 
M.D., LL.D., F.R.S., and Professor Scott Lang; Sydney, Pro 
fessor Liversidge, M.A., F.R.S. ; Tokyo (Imperial University of 
Japan} ; Upsala, Professor P. T. Cleve ; Victoria (Manchester, 
Liverpool, and Leeds], Principal Ward, Vice-Chancellor, and 
Professors Lodge, Osborne Reynolds, M Cunn, and Stroud ; 
Wales (University of], Principal Viriamu Jones and Professor 
Andrew Gray, LL.D., F.R.S. ; Washington (Columbian University], 
Professor Cleveland Abbe. 


Aberystwith (University College], R. D. Roberts, M.A., D.Sc. ; 
Bangor (University College of North Wales], Professor Andrew 
Gray, LL.D., F.R.S. ; Belfast (Queen s College), Rev. Thomas 
Hamilton, D.D., LL.D., President, and Professor Purser, LL.D. ; 
Cork (Queen s College], Professor Bergin, M.A. ; Dublin (Royal 
College of Science for Ireland} ; Galway ( Queen s College], Sir 
Thomas Moffett, LL.D.; London (City and Guilds Technical 
College, Finsbury}, Professor Silvanus P. Thompson, D.Sc., F.R.S.; 
London (Royal College of Science], Professor W. A. Tilden, D.Sc., 
F.R.S.; London (University College}, Professor Ramsay, F.R.S.; 
Newcastle - on - Tyne (Durham College of Science}, Professor 
Philipson, M.D. ; Oxford (Balliol College}; Paris (Ecole 
Normale Superieure}, Professor Violle. 


Amsterdam (Royal Academy of Science] ; Baltimore (Mem 
bers of Sir William Thomson s Class of 1884, Johns Hopkins 
VOL. II 2 C 


University)^ Professor Cleveland Abbe ; Berlin (Royal Prussian 
Academy of Sciences) ; Cambridge (Bachelors and Undergraduates 
of University of), F. W. Lawrence, B.A., and Philip W. Wilson ; 
Christiania (Students of the University of), Cato Aall ; Copen 
hagen (Royal Danish Society of Sciences], Professor Christiansen ; 
Cracow (Academy of Letters) ; Dublin (Science and Art Depart 
ment) ; Edinburgh (Educational Institute of Scotland), John 
Dunlop, F.E.LS. ; Edinburgh (Scottish Geographical Society ), Sir 
Renny Watson ; Erlangen (Physikalisch-medicinische Societdt zu 
Erlangen) ; Glasgow (Faculty of Physicians and Surgeons), Bruce 
Goff, M.D., President ; Glasgow (Geological Society), Sir Archibald 
Geikie, F.R.S., and J. Barclay Murdoch, Esq. ; Glasgow (School 
Board of), Sir John N. Cuthbertson, LLD., and Rev. William 
Boyd, LL.D. ; Glasgow (Students of University of), John S. 
Thomson, President of the Students Representative Council ; 
Gottingen (Royal Society of Science), Professor Woldemar Voigt ; 
Helsingfors, Finland (Society of Sciences) ; Liege (L Association des 
Inglnieurs Electriciens Sortis de Vlnstitut Montefiore) ; Lille 
(Students of University of) ; London (Royal Society), Sir Joseph 
Lister, M.B., P.R.S; London (British Association for Advance 
ment of Science), Professor A. W. Riicker, F.R.S. ; London (Royal 
Institution of Great Britain), Professor Dewar, F.R.S. ; London 
(Mathematical Society), Major P. A. MacMahon, R.A., F.R.S. ; 
London (Royal Astronomical Society), A. Ainslie Common, LL.D., 
F.R.S. ; London (Physical Society), Captain W. de W. Abney, 
F.R.S. ; London (Chemical Society), Professor John M. Thomson; 
London (Institute of Chemistry of Great Britain and Ireland), 
Professor Ramsay, F.R.S.; London (Institution of Electrical 
Engineers), John Hopkinson, F.R.S. ; London (Institution of 
Civil Engineers), Sir Benjamin Baker, K.C.M.G., F.R.S. ; 
London (Society of Engineers), Henry O Connor, Esq. ; London 
(Society for E?icourageme?it of Arts, Manufactures, and Com 
merce); London (Glasgow University Club) ; Manchester (Literary 
and Philosophical Society), Professor Schuster, F.R.S. ; Milan 
(Reale Instituto Lombardo di Scienze e Lettere), General Annibale 
Ferrero ; Modena (Royal Academy of Science, Letters, and Arts), 
General Annibale Ferrero ; Montreal (Canadian Society oj Civil 
Engineers), James Ross, Esq. ; Moscow (Imperial Society of 
Naturalists), Professor Oumov ; Munich (Der Konigliche Bayer- 
ischen Akademie der Wissenschaften) ; Newcastle-on-Ty?ie (Students 
of Durham College of Science) ; New York (National Electric 
Light Association of America), Thomas C. Martin, Esq. ; Paris 
(Conservatoire National des Arts et Metiers), Professor Violle ; 
Philadelphia (American Philosophical Society), Dr. J. Cheston 
Morris ; Rome (Italian Society of Science), General Annibale 

xxm THE JUBILEE 971 

Ferrero ; Rome (R. Accademia dei Lincei], General Annibale 
Ferrero ; Rotterdam (Batavian Society of Experimental Philo 
sophy), Dr. Elie van Rijckevorsel ; Scottish Amicable Life 
Assurance Society, Colin Dunlop, Chairman ; Scottish Universities 
(Students of the four), J. R. Hunter, Edinburgh University ; 
Tokyo (former Students from Japan in Lord Kelviris Class, now 
at Tokyo] ; Vienna (Imperial Academy of Sciences] ; Washington 
(National Academy of Sciences], Professor Simon Newcomb ; 
Washington (Philosophical Society], 

It is impossible to give at length the text of all 
the addresses mentioned in this list, but the follow 
ing representative ones are of special interest : 
From the Royal Society 

DEAR LORD KELVIN The President, Council and Fellows 
of the Royal Society desire on the happy occasion of the 
Jubilee of your Professoriate in the University of Glasgow not 
only to be represented, as they are, by their highest Officers 
the President and Treasurer, but also to assure you, by some 
direct words, of the warm sympathy of the whole Society. 

There is no need to dwell on the many ways in which you 
have contributed to that improvement of natural knowledge to 
secure which the Society was founded, or on the many valuable 
communications with which you have enriched the Society s 
records. Since you first joined the Society, and the Jubilee of 
that event is not far off, the Society has always known how 
much your belonging to it has added to its strength : but it 
has been especially during the recent five years, which went 
too swiftly by, while you filled in so admirable a manner the 
chair of President, that the Society has felt how close are the 
ties which bind it to you and you to it. 

We ask you to receive our heartiest congratulations on the 
present glad event, and our warmest wishes for your welfare in 
the years yet to come. JOSEPH LISTER, President. 

From the Institution of Electrical Engineers 

We, the President, Council, and Members of the Institution 
of Electrical Engineers, desire hereby to offer to your Lordship 
our sincere and hearty congratulations on the occasion of the 
Jubilee of your Professorship of Natural Science in the Uni 
versity of Glasgow. It will ever be a source of pride and satis 
faction to this Institution, that one who occupies so pre-eminent 


a position in the scientific world should have been its First 
President in 1889, besides having been an original member 
and President in 1874 of the same Association when it existed 
under the name of the Society of Telegraph Engineers. Not 
only have you contributed more than any other living man to 
our knowledge of the laws of nature, but you have found time 
to perfect practical applications of Science, wherefrom every 
branch of the Electrical Engineering Profession has derived 
special benefit. We desire, in conclusion, to express our fervent 
wish that you may continue for many years to enjoy the blessing 
of good health, and that Science may still further benefit from 
your labours. 

J. HOPKINSON, President. 

F. H. WEBB, Secretary. 

From the British Association for the Advancement 
of Science 

MY LORD The Council of the British Association for the 
Advancement of Science desire to offer to you their sincere 
congratulations on the completion of the fiftieth year of your 
tenure of the Professorship of Natural Philosophy in the Uni 
versity of Glasgow. 

It is unnecessary to recount the triumphs you have won 
during the last half-century in mastering the difficulties which 
beset the advance of scientific theory and experiment, and in 
applying scientific principles to the practical service of man. 
The record of your achievements is fresh in the minds of those 
who address you, and can never be effaced from the history of 
the development of mathematical and experimental physics, of 
engineering, and of navigation. We would rather therefore 
recall the long and close connection which has existed between 
the British Association and yourself. 

A regular attendant at our meetings, you have not only 
enriched our reports with many important papers, but have en 
couraged the efforts of younger men by never-failing sympathy 
and interest in their work. 

You have been President of the Mathematical and Physical 
Section of the Association no less than five times. You were 
President of the Association at Edinburgh in 1871, and have 
since then been a Life Member of our Council. 

As colleagues, then, we wish to tell you of the pride with 
which we, in common with all your fellow-countrymen, regard 
your distinguished career; and of the feelings of personal 
attachment with which we express the hope that you may long 



be spared to enjoy in health and strength the honours you have 
so nobly won. 

Signed on behalf of the Council, 


The address from the University of Edinburgh 
contained the following passage : 

We know not whether most to admire in you the acute 
Mathematician, the unwearied Investigator of Physical Problems, 
the skilled Electrician, or the resourceful Engineer ; to you in 
all of these capacities is due the success of Long-line Submarine 
Telegraphy, with the innumerable benefits resulting from the 
power of practically instantaneous communication between all 
parts of the globe. 

We are grateful for the lustre which your brilliant discoveries 
have shed upon our Scottish Universities, and we are proud to 
number you among our Colleagues. 

From the Master and Fellows of Peterhouse^ 

and Fellows of Peterhouse, on the occasion of the Jubilee of 
your Professorship of Natural Philosophy in the University of 
Glasgow, desire to express our profound admiration of the 
splendid discoveries in physical science, and of the valuable 
scientific inventions, which have characterised the tenure of 
your professorship and have conferred signal benefits upon the 
whole civilised world ; as well as our gratification and pride that 
your name, so indissolubly connected with the progress of 
science in the nineteenth century, should have been for a period 
of fifty -five years closely connected with this ancient college 
as Student, Scholar, Fellow, again Fellow honoris causa and 

We recall with pleasure your noble enthusiasm as an under 
graduate in the pursuit of your mathematical studies, and your 
important contributions to scientific journals, which led our late 
Master, Dr. Cookson, and your private Tutor, Mr. W. Hopkins, 
also a distinguished member of the College, at that early period 
of your career to predict your future eminence in science, and 
your keen interest in manly sports shown by your success as an 
oarsman in winning the Colquhoun Sculls, and in rowing in the 
College boat, which then occupied the second place on the river. 

Many of us, students in your Natural Philosophy Class in 


the University of Glasgow, have enjoyed the privilege of listening 
to your inspiring lectures; all of us, as your colleagues in the 
governing body of Peterhouse, have warmly appreciated your 
unfailing courtesy, wise counsels and generous sympathy with 
all that concerns the welfare of the College. We bear in grate 
ful remembrance your munificence on the occasion of the 
celebration of the Six Hundredth Anniversary of the foundation 
of our most ancient House. 

We fervently pray that your connection with the College may 
long continue. 

In testimony whereof, we have attached our common seal 
this thirteenth day of June, in the year of our Lord, One 
thousand eight hundred and ninety-six. 

From the Students of the University of Glasgow 

MY LORD In the name of the Students of the University 
of Glasgow we desire to offer you our sincere and hearty con 
gratulations on the occasion of your Jubilee as Professor of 
Natural Philosophy in our University. While we feel it needless 
to dwell upon your pre-eminence in the world of science, and 
would not presume to speak of that genius which has enriched 
humanity by so many brilliant discoveries, we ask, simply as 
your students, to be allowed to take our part in the universal 
congratulation at this time. 

We rejoice to have an opportunity of expressing in your 
presence a feeling of affectionate regard no less strong than the 
admiration to which others besides ourselves are to-day giving 

Above all we desire to refer to your long unbroken connection 
with our University, a connection which must be endeared to 
you by many precious memories, and has been to successive 
generations of students a source of grateful pride. We are 
proud to think that, year after year, and decade after decade, 
our University has shared in your ever-increasing fame, and 
that for so long a period it has been her happiness to retain in 
her midst one whom all nations have delighted to honour. 

The last address that was presented was from 

The Senatus Academicus of the University of Glasgow 

MY LORD The rejoicings which have been arranged to 
celebrate the close of your fiftieth session betoken the admira 
tion and affection with which you are regarded by your colleagues 
in the Senate, but it is none the less fitting that on this auspicious 



occasion these feelings should find articulate expression in an 
address of congratulation. 

The fifty years during which you have occupied the chair of 
Natural Philosophy in this University have to an extent un 
paralleled in the history of the world been marked by brilliant 
discoveries in every department of Physical Science, and by 
the prompt adaptation of many of these discoveries to meet the 
practical needs of mankind. We recognise with admiration that 
in both these respects you have been a leader of the age in 
which we live. . . . But only your colleagues in University work 
are in a position to appreciate the versatility of faculty, the 
exhaustless energy, and the tenacity of purpose which have 
enabled you to grapple successfully with problems the most 
varied, and to reveal to us on every side the reign of order and 
law. In the midst of all, you have endeared yourself to us by 
the graces of your personal character, notably by that simplicity 
which, unmarred by honours or success, remains the permanent 
possession of transcendent genius, and by that humility of spirit 
which, the clearer the vision of truth becomes, bows with the 
lowlier reverence before the mystery of the universe. 

My Lord, the contemplation of a past so rich in achieve 
ments and honours encourages your colleagues to look forward 
to the future in the hope that you may have health and strength 
to win new triumphs in years to come, and long to remain 
among us the ornament and the glory of our ancient University. 

Then followed the giving of degrees. In the 
absence of Principal Caird, through illness, Sir 
William Gairdner, K.C.B., Professor of the Practice 
of Medicine, occupied the chair in the earlier part 
of the meeting during the presentation of Addresses, 
and also conferred the degree of LL.D. upon Lord 
Kelvin, who then took the chair and conferred the 
degree of LL.D. on the following : 

Professor Cleveland Abbe, Washington ; Professor Christian 
Christiansen, Copenhagen; Professor Per Theodor Cleve, 
Upsala ; General Annibale Ferrero, Ambassador from H.M. the 
King of Italy ; Professor Izidor Frohlich, Buda-Pest ; Professor 
Gabriel Lippmann, La Sorbonne, Paris ; Professor Archibald 
Liversidge, Sydney ; Professor Eleuthere Mascart, College de 
France ; Professor Henri Moissan, Paris ; Professor Simon 


Newcomb, Baltimore ; Professor Nicolas Oumov, Moscow ; 
Professor Emile Picard, Paris : Professor Georg Quincke, 
Heidelberg ; Professor Woldemar Voigt, Gottingen. 

Lord Kelvin then said : 

The University of Glasgow is honoured by the 
presence to-day of many distinguished visitors from 
distant countries, from America, from India, from 
Australia, and from all parts of the United Kingdom. 
Names of men renowned for their scientific work in 
foreign lands have been added to our list of honorary 
graduates. That I have had the honour of conferring 
these degrees in the name of the University is a subject 
of keenest regret to all here present, because it is due 
to the absence of Principal Caird, on account of illness. 
We hope that the beginning of next session will see him 
at home in the University with thoroughly recovered 
health. In his absence the duty of conferring degrees 
has fallen, according to University law, on me as senior 
Professor present. 

I am also one of the recipients of the degrees, and, 
in the name of all who have to-day been created Doctors 
of Laws of the University of Glasgow, I thank the Senate 
for the honour which we have thus received on the 
occasion of the Jubilee of my professorship. For myself, 
I can find no words to express my feelings on this 
occasion. My fifty happy years of life and work as 
Professor of Natural Philosophy here, among my students 
and my colleagues of the University, and my many kind 
friends in the great city of Glasgow, call for gratitude ; 
I cannot think of them without heartfelt gratitude. But 
now you heap coals of fire on my head. You reward 
me for having enjoyed for fifty years the privilege of 
spending my time on the work most congenial to me 
and in the happiest of surroundings. 

You could not do more for me if I had spent my life 
in hardships and dangers, fighting for my country, or 
struggling to do good among the masses of our popula 
tion, or working for the benefit of the people in public 

xxin THE JUBILEE 977 

duty voluntarily accepted. I have had the honour to 
receive here to-day a gracious message from His Royal 
Highness the Prince of Wales, and addresses from sister 
universities in all parts of the world ; from learned 
societies, academies, associations, and institutions for the 
advancement of pure and applied science ; from muni 
cipal corporations and other public bodies ; from sub 
marine telegraph companies, and from their officers, my 
old comrades in their work ; from students, professors, 
and scientific workers of England, Scotland, and Ireland, 
and other countries, including my revered and loved St. 
Peter s College, Cambridge. 

I have had an address also from my twenty Baltimore 
Coefficients of 1884. The term "coefficients" is abused 
by mathematicians. They use it for one of the two 
factors of the result. To me the professor and his class 
of students are coefficients, fellow-workers, each con 
tributing to whatever can possibly be done by their daily 
meetings together. I dislike the term lecture applied 
here. I prefer the French expression " conference." I 
feel that every meeting of a professor with his students 
should be rather a conference than a pumping-in of 
doctrine from the professor, perhaps ill understood and 
not well received by his students. The Scottish Uni 
versities have enabled us to carry out this French idea 
of conference. I think in every one of his classes the 
professor is accustomed to speak to his students, some 
times in the form of viva voce examination, and oftener, 
I hope, in the manner of interchange of thoughts, the 
professor discovering whether or not the student is 
following his lecture, and the student, by showing what 
he knows or does not know, helping the professor through 
his treatment of the subject. 

I have had interesting and kindly addresses from 
my old Japanese students of Glasgow University, now 
professors in the University of Tokyo, or occupying posts 
in the Civil Service and Engineering Service of Japan. 
I wish particularly also to thank my Baltimore Coefficients 
for their address. They have been useful to myself in my 


own keen endeavour unsuccessful, I must say, neverthe 
less keen to find out something definite and clear about 
light and ether and crystals. 

The addresses which I have received to-day contain 
liberal and friendly appreciation of all my mathematical 
and physical papers, beginning in 1 840 and ending 
not yet I hope. The small proportion of that long series 
of writings which has led to some definite advancement of 
science is amply credited for its results. A larger part, 
for which so much cannot be said, is treated with un 
failing and sympathetic kindness as a record of persever 
ing endeavour to see below the surface of matter. It has 
been carried on in the faith that the time is to come 
when much that is now dark in physical science shall be 
seen bright and clear, if not by ourselves, by our suc 
cessors in the work. 

I am much gratified by the generous manner in which 
these addresses have referred to the practical applications 
of science in my work for submarine telegraphy ; my 
contributions to the advancement of theoretical and 
practical knowledge of the tides ; my improvement in 
the oldest and next oldest of scientific aids to navigation 
the sounding plummet and the mariner s compass ; 
and my electric measuring instruments for scientific 
laboratories, for the observation of atmospheric electricity, 
and for electric engineering. 

I now ask the distinguished men who have honoured 
me by presenting to me these addresses, to accept for 
themselves personally, and for the societies represented 
by them, my warmest thanks for the great treasure which 
I have thus received goodwill, kindness, friendship, 
sympathy, encouragement for more work a treasure of 
which no words can adequately describe the value. 

I cordially thank the French Academy of Sciences 
for their great kindness in sending me by the hands of 
my loved arid highly esteemed colleague, Mascart, the 
Arago Medal of the Institute of France. 

I thank all present in this great assembly for their 
kindness, which touches me deeply ; and I thank the City 


and University of Glasgow for the crowning honour of 
my life which they have conferred on me by holding a 
commemoration of the Jubilee of my professorship. 

Professor Mascarfs Address 

Professor Mascart, who was the delegate of 
the College de France and of the Academic des 
Sciences, Paris, at the Jubilee, had intended to make 
the following speech when presenting the Arago 
Medal. He afterwards gave his manuscript to 
Lady Kelvin, and said that he had been too much 
touched by the ceremony to be able to deliver his 
address : 

MILORD ET CHER CONFRERE L Acade"mie des Sciences de 
Paris, dans laquelle vous etes aujourd hui le doyen des associes 
Grangers, a voulu se joindre aux savants de tous les pays du 
monde, k vos admirateurs, a vos amis, pour vous app.orter des 
felicitations chaleureuses a 1 occasion du cinquantenaire de votre 
arrivee comme professeur k 1 Universite de Glascou que vous avez 
tant illustre e. 

II y a quelques mois, 1 Institut de France celebrait le centieme 
anniversaire de sa fondation, ou plutot de la reconstitution des 
anciennes Academies sur des bases plus larges. Nous ne 
pouvons oublier 1 elevation de langage avec laquelle le President 
de la Societe Royale de Londres vint alors traduire les sentiments 
de cordialitd de cette grande et celebre Institution. 

Dans une autre reunion, ou vous parliez en votre nom 
personnel, vous nous avez caus une profonde Emotion en 
declarant que vous aviez une dette de reconnaissance envers 
notre pays, que nos grands esprits tels que Fourier, Laplace et 
Sadi Carnot avaient e"t vos inspirateurs et que vous consideriez 
la France comme Valma mater de votre jeunesse scientifique. 

Si la dette existe, vous 1 avez paye"e avec usure. Dans la 
longue sdrie de travaux et de de"couvertes qui galonnent votre 
admirable carriere, une des plus nobles que 1 on puisse rever, 
vous avez aborde toutes les questions de cette science h laquelle 
la litterature anglaise conserve le beau nom de "philosophic 
naturelle," soit pour contribuer aux progres des conceptions 
th^oriques, soit pour en de duire des applications utiles au 
deVeloppement de 1 industrie et au bien de 1 humanitd 


Quoi que 1 avenir reserve aii genie inventif de 1 esprit humain, 
votre nom restera comme ayant ete le guide le plus sur dans une 
epoque feconde et le veritable educateur de la generation actuelle 
dans le domaine de I electricite. 

Je suis particulierement heureux que 1 Academie des Sciences 
m ait confie le soin de vous remettre une medaille d or a 1 effigie 
d Arago, medaille qu elle reserve pour rendre hommage aux 
services exceptionnels rendus a la science et qui porte cette 
devise : " Laudes damus posteri gloriam." 

Vos confreres de 1 Institut de France esperent que vous 
voudrez consid^rer ce souvenir comme un temoignage de haute 
estime et de leurs sentiments les plus affectueux. 

Dans une circonstance a laquelle je faisais tout a 1 heure 
allusion, vous avez rapped aussi qu au debut de votre carriere 
vous aviez frequente les laboratoires du College de France, ou 
les professeurs de cette epoque, Biot, Liouville et Victor 
Regnault accueillirent avec empressement le jeune homme dont 
les premieres publications faisaient deja prevoir le brillant 

L Assemblee de Professeurs du College a bien voulu, par une 
deliberation speciale, me confier la mission de vous temoigner 
le prix qu elle attache a ce souvenir en vous apportant le tribut 
de ses cordiales felicitations. 

J ai encore comme President actuel de la Societe d En- 
couragement pour 1 Industrie Nationale, a vous traduire les 
hommages de cette association, fondee a 1 origine du siecle et 
qui a pour but de faciliter Fapplication des d^couvertes scien- 
tifiques aux progres industriels. 

II y a deux ans, la Societe avait 1 honneur de vous d- 
cerner Tune de ses plus hautes recompenses, par 1 attribution 
d une medaille de platine a 1 effigie d Ampere. Vous estimerez 
sans doute que les figures d Arago et d Ampere, placees cote a 
cote dans la collection de vos ecrins, ne s y trouveront pas en 
mauvaise compagnie, de meme que les deux savants ont e^e 
associes de si pres dans leurs immortelles decouvertes. 

Enfin vous avez eu a diverses reprises 1 occasion de tdmoigner 
une bienveillance particuliere a la Societe Internationale des 
Electriciens en assistant a quelques-unes de ses stances et en 
honorant de votre concours le Congres de 1889. 

La Societe m a prie d etre son interprete dans la circonstance 
actuelle, pour vous exprimer ses sentiments de reconnaissance, 
son admiration pour vos travaux, et pour vous offrir des res- 
pectueux hommages. 



On the evening of Tuesday, June 16, Lord 
Kelvin was entertained by the Corporation and 
University of Glasgow at a Banquet in St. Andrew s 
Hall. After dinner, Sir James Bell, Bart., the 
Lord Provost, who presided, read a message from 
the Queen as follows : 

The Queen commands me to beg that you will kindly ex 
press to Lord Kelvin Her Majesty s sincere congratulations on 
the occasion of the Jubilee of his professorship in the Glasgow 
University. Her Majesty trusts that many years of health and 
prosperity may be in store for him and Lady Kelvin. The 
Queen is particularly gratified at the presence of so many 
eminent representatives from all countries of the world, who 
have come to do honour to your distinguished guest. 

ARTHUR BIGGE, on behalf of 

The Lord Provost, on rising to propose the 
toast of the evening, said 

We have received one or two cable messages which I have 
been desired to read. They are addressed to Lord Kelvin. 
The first is from Toronto, and reads as follows : " The Councils 
of the University of Toronto and of University College offer you 
their heartiest congratulations on your attainment of your fiftieth 
year of your professorship, and they earnestly wish that you 
may be long spared to serve science, whose advancement you 
have so signally promoted. J. Loudon, President." Then 
from Quebec there is one : " I send most cordial congratulations 
on this occasion. Your illustrious fifty years services have been 
of great profit to science. La Flamme." Another telegram, 
just received from Moscow, is addressed : " To the celebrated 
Lord Kelvin, famous, learned, we send our congratulations. 
The Moscow University students." In addition to these 
telegrams, I have been requested to say that numerous letters 
have been received expressing, on behalf of the writers, regret 
at inability to be present at these celebrations. I have one from 
Lord Salisbury expressing his great regret. Mr. Campbell has 
intimated one that he has had from Sir John Gorst, and there 
are many others. I wish to read one from Principal Caird. 
Need I say how greatly we all regret the cause by which we are 
unavoidably deprived of his presence, and of the matchless 


eloquence with which he would have presented the toast which 
in his absence falls to me to-night. 

I know how far more deeply than can be expressed in words 
our beloved Principal grieves over his inability to be with us 
to-night, but we confidently hope that he may soon again be 
restored to health. 

Ladies, my Lords, and Gentlemen, The toast that I have 
now the honour to propose for your acceptance is that of " Lord 
Kelvin, and hearty congratulations on the attainment of his 
professorial Jubilee." These congratulations are manifold and 
great they come from all European countries ; they come from 
India and our Colonies, from across the Atlantic, from the 
great scientific societies and from the leading scientists of to-day ; 
and in this City we are doing what is for us unique the 
University and City authorities are joining hand in hand to 
show, in the strongest manner possible, our intense admiration 
and appreciation of Lord Kelvin and his work. A great social 
and commercial revolution dates from August 1858, when the 
message was signalled under the ocean, " Europe and America 
are united by telegraphic communication. Glory to God in the 
highest, on earth peace and goodwill towards men." 

To almost every branch of scientific research Lord Kelvin 
has given contributions of inestimable value. In regard to the 
laws of heat, he has been one of the greatest discoverers ; while, 
through the perfecting of the compass and improving the means 
of sounding, the risk of loss of life or vessel has been so mini 
mized that I do not think I am overstating the case when I 
say that these two discoveries have saved thousands of lives, 
and millions of pounds worth of property. 

Lord Kelvin s discoveries and appliances have world-wide 
use, from the most complicated and delicate instrument to im 
provements on the simplest form of mechanism. His industry 
is unwearied, and he seems to take rest by turning from one 
difficulty to another difficulties that would appal most men, 
and be taken as enjoyment by no one else. But what has been 
the result of these great gifts of genius, coupled with this 
industry ? They have resulted in a lifetime of discoveries fraught 
with good ; year by year something has been accomplished ; 
paper after paper that are standards on their subject-matter have 
been written until we are lost in amazement at what has been 
done. While concurrently with this active productivity his 
lordship s university classes have been carefully carried on. How 
many students in these fifty years of Jubilee have been fired 
with their teacher s enthusiasm we can never know, but from 
this class many have gone who have attained great distinction 



and who look back with pride and pleasure to the days passed in 
the Natural Philosophy class-room of Glasgow University. 

My Lords and Gentlemen, it is given to few men to labour 
in one place for fifty years ; it is given to almost none to do so 
with the distinction achieved by our guest, a distinction now 
so great that he may justly be called the greatest living scientist. 
Lord Kelvin has given in America the Baltimore lectures 
lectures not given to students but to professors. He was a 
member of the Niagara Commission. He has been awarded 
honours innumerable and of every kind from learned societies in 
the Old World and the New, and, as you know, he has just de- 
mitted the office of President of the Royal Society, after a term 
of office marked by the greatest brilliancy. This life of un 
wearied industry, of universal honour, has left Lord Kelvin with 
a lovable nature that charms all with whom he comes in contact. 

Lord Kelvin, indeed, inspires love and reverence in all. His 
home life is love and melody. His helpmate is worthy of him, 
and greater cannot be said. Those who have the great privilege 
of their friendship, with fervent prayer, will in their hearts add to 
the toast the wish that Lord and Lady Kelvin may long be spared 
to one another. 

Lord Kelvin, who on rising to reply was greeted 
with prolonged applause, said : 

First of all, I desire to express the deep and heartfelt 
gratitude with which I have heard the most kind and gracious 
message from Her Majesty the Queen, which has been read to 
us by the Lord Provost. But I cannot find words for thanks. 
I can only, on the part of Lady Kelvin and myself, tender an 
expression of our loving loyalty to the Queen. My Lord 
Provost, my Lords, and Gentlemen, I thank you with my whole 
heart for your kindness to me this evening. You have come 
here to commemorate the Jubilee of my University professorship, 
and I am deeply sensible of the warm sympathy with which you 
have received the kind expressions of the Lord Provost regarding 
myself in his review of my fifty years service, and his most 
friendly appreciation of practical results which have come from 
my scientific work. 

I might perhaps rightly feel pride in knowing that the Uni 
versity and City of Glasgow have joined in conferring on me 
the great honour of holding this Jubilee, and that so many 
friends and so many distinguished men friends and comrades, 
day-labourers in science have come from near and far to 
assist in its celebrations, and that congratulations and good 


wishes have poured in on me by letter and telegram from all 
parts of the world. I do feel profoundly grateful. But when 
I think how infinitely little is all that I have done I cannot feel 
pride ; I only see the great kindness of my scientific comrades, 
and of all my friends in crediting me for so much. 

One word characterises the most strenuous of the efforts for 
the advancement of science that I have made perseveringly 
during fifty-five years ; that word is FAILURE. I know no 
more of electric and magnetic force, or of the relation between 
ether, electricity, and ponderable matter, or of chemical affinity, 
than I knew and tried to teach to my students of natural 
philosophy fifty years ago in my first session as Professor. 
Something of sadness must come of failure ; but in the pursuit 
of science, inborn necessity to make the effort brings with it 
much of the certaminis gaudta, and saves the naturalist from 
being wholly miserable, perhaps even allows him to be fairly 
happy in his daily work. 

And what splendid compensation for philosophical failures 
we have had in the admirable discoveries by observation and 
experiment on the properties of matter, and in the exquisitely 
beneficent applications of science to the use of mankind with 
which these fifty years have so abounded ! You, my Lord 
Provost, have remarked that I have had the good fortune to 
remain for fifty years in one post. I cordially reply that for 
me they have been happy years. I cannot forget that the 
happiness of Glasgow University, both for students and pro 
fessors, is largely due to the friendly and genial City of Glasgow, 
in the midst of which it lives. To live among friends is the 
primary essential of happiness ; and that, my memory tells me, 
we inhabitants of the University have enjoyed since first I came 
to live in it (1832) sixty-four years ago. And when friendly 
neighbours confer material benefits, such as the citizens of 
Glasgow have conferred on their University in so largely helping 
to give it its present beautiful site and buildings, the debt of 
happiness due to them is notably increased. 

I do not forget the charms of the old college in the High 
Street and Vennel, not very far from the " comforts of the Salt- 
market." Indeed, I remember well when, in 1839, the old 
Natural Philosophy class-room and apparatus-room (no physical 
laboratory then) was almost an earthly paradise to my youthful 
mind ; and the old College Green, with the ideal memories of 
Osbaldistone and Rashleigh and their duel, created for it by 
Sir Walter Scott, was attractive and refreshing to the end. But 
density of smoke and of crowded population in the adjoining 
lanes increased, and the pleasantness, healthiness, and convenience 



of the old college, both for students and professors, diminished 
year by year. If, my Lord Provost, your predecessors of the 
Town Council, and the citizens of Glasgow, and well-wishers to 
the city and its University all over the world, and the Govern 
ment, and the great railway company that has taken the old 
college, had left us undisturbed on our ancient site, I don t 
believe that attractions elsewhere would have taken me away 
from the old college ; but I do say that twenty- five of the fifty 
years of professorship which I have enjoyed might have been 
less bright and happy, and I believe also less effective in respect 
to scientific work, than they have been with the great advantages 
with which the University of Glasgow has been endowed since 
its migration from the High Street. 

My Lord Provost, I ask you to communicate to your 
colleagues of the Town Council my warmest thanks for their 
great kindness to me in joining to celebrate this Jubilee. Your 
Excellency, my Lords and Gentlemen, I thank you all for the 
kind manner in which you have received the toast of my health 
proposed by the Lord Provost, and for your presence this 
evening to express your good wishes for myself. 

Professor Sir W. T. Gairdner, in proposing the 
toast of the Representatives present from other 
Universities and learned bodies, spoke of Lord 
Kelvin s personal character as it had appeared to 
his colleagues, and said : 

I feel very strongly that all that has been said of the scientific 
eminence of Lord Kelvin, and of his innumerable and most 
remarkable discoveries in science, leaves still without emphasis 
one point about him which only those who have been in close 
association with him can appreciate, and that is his childlike 
humility of character his very remarkable power of inspiring 
affection as well as esteem, his interest and sympathy with every 
one who is related to him in any way whatever. 

His Excellency General Annibale Ferrero, 
Lord Lister, and Professor Simon Newcomb of 
Washington responded to this toast ; and among 
the later speakers were Professor Story, the Earl 

of Rosse, Sheriff Berry, and Sir Henry Roscoe. 
VOL. IT 2 D 


The Italian Ambassador s speech was as 
follows : 

MESSIEURS Lorsque Ton m a fait 1 honneur de me charger 
de prendre la parole au nom de tant d hommes illustres, j ai 
pense que ce serait une grande temerite de ma part que 
d accepter un role qui aurait convenu a des illustrations dont le 
nom a deja une place dans 1 histoire de la science. Cependant 
j ai pense que j avais 1 honneur de representer la patrie des 
grands predecesseurs de Lord Kelvin, tels que Galilee, Volta, 
et Galvani. En venant representer les institutions scientifiques 
de nos pays respectifs, nous avons avant tout voulu rendre 
hommage a 1 homme de genie dont on celebre le jubil et k 
1 Universite de Glascou qui a la gloire de le posseder. Mais 
notre presence est aussi pour prouver que le monde scientifique 
tout entier veut prendre sa part de 1 honneur que Lord Kelvin a 
rendu a la race humaine. La lumiere qui resplendit aujourd hui 
sur 1 Universite de Glascou est comme celle du soleil. Elle 
n appartient pas a un seul pays, mais s etend sur toute I humanite. 
Nous devons des remerciments speciaux a 1 illustre professeur 
Gairdner pour la sante qu il vient de porter aux representants 
des institutions scientifiques. Nous devons payer un tribut de 
vive reconnaissance a la ville et a 1 Universite de Glascou pour 
1 accueil si cordial et honorifique qui nous a ete accorde. C est 
avec le plus grand sentiment d admiration que nous avons assiste 
a ce jubile vraiment grandiose, digne de 1 Universite qui 1 a 
organise", et du grand homme qui en a e*t 1 objet. Le spectacle 
sublime auquel nous avons assiste ce matin a autant elevd notre 
esprit que touche notre cceur. Je ne puis mieux exprimer 
notre pensee comme qu en disant que nous avons assist^ a 
1 apotheose de la science. Je veux finir en exprimant le vceu 
le plus cher a 1 Universite de Glascou et a nous-memes, c est-a- 
dire que la Providence, laquelle lui a con fie dans la personne 
de Lord Kelvin un tresor incalculable, lui conserve pour des 
longues annes ce tresor precieux a 1 humanite toute entiere. 

The University Senate had arranged that the 
celebrations should terminate on Wednesday with a 
sail through some of the more picturesque parts 
of the Clyde. A company of about two hundred 
and fifty, including Lord and Lady Kelvin and a 
large number of the delegates and visitors, were 



conveyed by special trains to Greenock, where they 
embarked on board the steamer Glen Sannox. The 
route followed was by Largs and Millport, and then 
northwards along the western coast of the Island of 
Bute, through the Kyles, and thence homeward. 

Perhaps the most striking thing about the Jubilee 
of Lord Kelvin was its spontaneity ; indeed the 
absence of officials from the ceremonies was the 
cause of comment at the time. A writer in the 
Saturday Review, drawing a comparison between 
the careers of Lord Kelvin and of von Helmholtz, 
each of whom had lived to celebrate his Jubilee, 
pointed out the difference between England and 
Germany in the public estimation in which science 
is held and honoured : 

Though it is the fact that Lord Kelvin and von Helmholtz 
were each honoured by a title of nobility, the difference in the 
recognition is truly striking. It was not until Sir William 
Thomson began to dabble in politics that the great and wise and 
eminent in official circles discovered those transcendent claims to 
recognition which had long been patent in the world of science. 
Whereas the German Emperor, in conferring a patent of nobility 
upon von Helmholtz, specially commented on his abstention 
from intermeddling with political questions. 

At the Helmholtz Jubilee in 1891, the ceremonials in Berlin 
were marked by the presence of two Secretaries of State, the 
Minister of the Interior and the Minister of Education. Thus 
did Germany set her official approbation upon the honours 
acclaimed by the assembled representatives of science. At the 
Kelvin Jubilee official recognition seems to have been studiously 
withheld. Neither the Lord President of Council nor the 
Secretary of State for Scotland put in an appearance. The 
Chancellor of the University of Glasgow was conspicuous by his 
absence. The Prince of Wales, who, in the absence of political 
officials, might have represented the Sovereign, was detained " by 
long-standing engagements ... in the south." . . . The King 
of Italy could send an Ambassador. But Italy is one of those 
countries where science is honoured for its own sake. 


The following contemporary narrative from 
the pen of his grand-niece Miss Margaret E. 
Gladstone adds a few graphic details : 

The Graduation ceremony next morning was the best of all 
the functions. It began by the presentation of over eighty 
addresses from all parts of the world (at least before that, the 
students whiled away the time by singing, " Here a poor buffer 
lies low," and when Uncle William came in " Jolly Good Fellow "), 
and then we had a Latin prayer and a letter from the Prince 
of Wales. The gowns and uniforms of the delegates were most 
varied and gorgeous : the foreigners came first, and then the 
representatives of the various British Universities and learned 
societies, and of the students of different Universities ; each man 
with his roll or book tucked away under his arm. Each one 
shook hands with Uncle William and some of them made little 
speeches. Mascart, who brought several Addresses from France, 
and the Arago gold medal, had prepared a nice little speech, but 
was too touche to say anything when it came to the time. He 
and Moissan and Max-Miiller wore the French Academicians 
dress green palm-leaves embroidered on a black ground and 
looked very fetching. The Lille professors had orange gowns ; 
but the most gorgeous of all was the Italian Ambassador, with 
rows of orders across his uniform. 

After the addresses, Professor Gairdner gave Uncle William 
the LL.D. of Glasgow (how pleased old Macpherson, the 
janitor, must have been to put on his hood !), which was quite 
illegal, for it ought to have been conferred by the Chancellor, 
Lord Stair, or the Vice- Chancellor, Principal Caird, both 
of whom were away ill, or, after them, by the Senior Professor, 
who is Uncle William himself. However, he took the chair 
after that, and did the capping of the foreigners who got 
degrees. The students made a little banging each time the 
velvet cap descended, and shouted out a few remarks ; but on 
the whole they were remarkably quiet and suppressed. Sir 
Joseph Hooker told us he missed the pea-shooting which went 
on so much at the time he was a fellow - student with James 
and William Thomson in my great-grandfather s class. After the 
capping Uncle William made his reply. Some of us were quite 
afraid he was going to break down, he got so pale, and the effort 
to find words seemed too much for him, but he drank a little 
water with whisky in it, and then got on all right. I thought his 
speech was beautiful. So did every one. 



In the evening the word " Failure " in which he characterized 
the results of his best efforts seemed to ring through the hall 
with half-sad, half-yearning emphasis. Some of the people tried 
to laugh incredulously, but he was too much in earnest for that. 

Yet at the same time it was not pessimistic, for it was so evident 
what keen joy he had had in his work, and still has, and how 
warmly he feels the help and affection of his fellow-workers. I 
should think on the whole he has had as happy a life as any one 
can, and happy because of his utter devotion to his work, and his 
thoroughness in throwing himself into whatever is before him, 
and constant readiness to learn. 

As for the students, I am afraid they laughed, with good 
cause, when he spoke of the ideal lecture as a conference, because 
I always hear that he goes up in the heights when he is lecturing 
to them, and pours forth speculations with great enthusiasm far 
above their heads. They are, however, very fond of him : they 
serenaded him at three o clock in the morning of Tuesday, after 
their rowdy Gaudeamus at the Union ; only, fortunately, he slept 
through it. On Wednesday, when our steamer passed the one 
on which they were all, on an excursion, and Uncle William got 
up on our paddle-box to wave to them, the cheering and waving 
were tremendous ; and they came up in the evening after that to 
his house and he went out and gave a little speech, telling them 
to go back to their work, for that was the best thing for every 
one whereat they groaned and howled ; and that it had been 
good for them to have a jollification whereat they cheered lustily. 

In thinking over Uncle William s speeches, the tone in which 
he gave them, and his quiet, serious, deferential look when praise 
was heaped upon him, dwell in my memory. There was some 
thing pathetic about it all a sort of wonder that people should 
be so kind to him, and a wish that he had done more to deserve 
it all. 

I forgot to say that at the close of the banquet we all sang 
" Auld Lang Syne " at Uncle William s request. 

Many of the scientific men went off that night or next day, 
but a good number were left to go on the steamboat excursion 
next day on the Glen Sannox. It pelted all the morning, but 
we were very happy chattering under an awning or down in the 
saloon ; and we could just see Netherhall looming through the 
mist as we past it and fired off two guns. Then, while we were 
down at lunch, it cleared up and we came up to find ourselves 
close to Arran, with the most beautiful sunshine and cloud effects. 


We came back by the Kyles. ... In the middle of the afternoon 
some of them got up the Lancers on deck, and it was great fun to 
see Aunt Fanny leading off with Professor Ferguson, till a 
sudden squall of rain came on, and they had to fly. . . . 

Uncle William is simply marvellous : he is seventy-three, and 
has been ill all winter and spring (I think, though, that being 
kept partly a prisoner by his bad leg has been better for him than 
rushing round society functions, and endless meetings), and yet 
after all he had gone through, both of physical and mental (and 
emotional) exertion in the past few days, and an Address from, 
and a speech to, the Liberal Unionist Association that morning, 
he was quietly alert, taking in all the Addresses, and all that 
was going on in the bustle ; and then when we came in to 
tea talking away with my father about chemical theories, and 
about the terrible shipwreck there has been, and everything that 
turned up. 

The next day we came up with them in the same train. At the 
last minute his green-book was left behind, so he had to content 
himself with answering his telegrams (they had written twenty-two 
telegrams before we lunched with them at Preston) and writing 
letters to Quincke, Stokes, and James Bottomley on Rontgen 
rays, etc. Then by 9 P.M. he was taking the chair at the Royal 
Institution, and, as Aunt Fanny said, seemed better than before 
he went down to Glasgow. He appreciated the beauty of the 
country too on the way up, and thought I was using my time well 
by looking out of the window a good deal it certainly was a 
perfect day, with blue sky and sunshine, and clouds to give rich 
shadows, and then the grass and young corn such a bright green, 
and the haymakers in the fields, and the hedges lovely with wild 

A week afterwards Lord Kelvin addressed to the 
various persons who had sent letters or presented 
felicitations, a lithographed autographic letter, as 
follows : 

June 23, 1896. 

Lord Kelvin is much gratified by welcome letters 
containing congratulations on the occasion of the Jubilee 
of his Professorship, and highly valued good wishes, and 
kind words, which have come to him from many friends. 



He is very sorry that it is impossible for him to write in 
reply to each. He desires now to express his heartfelt 
thanks to all for the great kindness and sympathy which 
he has received. 

Lord and Lady Kelvin were invited by Her 
Majesty Queen Victoria to dinner at Windsor Castle 
on Monday, July 13, 1896, and to remain until the 
following day. The Marquis and Marchioness of 
DufTerin and the Duke and Duchess of Argyll were 
amongst the guests. After dinner they all sat in 
the corridor, and one after another of the guests 
was brought up to speak to Her Majesty, at her 
request. When Lady Kelvin came to her she said 
to her: " It is a long time since we have met, not 
since we were at Inveraray Castle." That was in 
1 875 (see p. 663). She then inquired how Lord Kelvin 
had been. To Lord Kelvin she talked of his Jubilee. 
They could not help noticing that the Queen was 
very lame and infirm, and of failing eyesight. 

On Wednesday, July 15, Her Majesty held an 
investiture at Buckingham Palace, when she con 
ferred on Lord Kelvin the Grand Cross of the 
Royal Victorian Order. As he approached the 
presence to receive the decoration, H.R.H. the 
Duke of Connaught whispered to the Queen that 
it was Lord Kelvin. At once she said : " Lord 
Kelvin must not kneel, it might hurt his leg." 

Later in the same afternoon Lord Kelvin 
attended at the Victoria Institute to hear the 
Address by Sir George Stokes. 


In commemoration of the centenary of Robert 
Burns a statue of Mary Campbell (" Highland 
Mary ") was unveiled by Lord Kelvin at Dunoon, 
on August i, 1896. 

On August 12, returning to Largs with Lady 
Kelvin, he was met at the railway station by the 
Provost and Magistrates of that burgh, and pre 
sented with an address of congratulation on his 
recent Jubilee. 

A month later, Lord and Lady Kelvin were 
staying at Knowsley during the meeting of the 
British Association at Liverpool, under the presi 
dency of Sir Joseph (afterwards Lord) Lister. Lord 
Kelvin read three papers : one, an Attempt to 
explain Chemical Affinities by Molecular Dynamics; 
another (in association with two of his pupils), on 
the Communication of Electricity from Steam to 
Air ; a third (in collaboration with J. T. Bottomley 
and M. Maclean), on the Measurement of Electric 
Currents through Air. 

All this autumn Lord Kelvin suffered at intervals 
from acute facial neuralgia, seated in the " fifth 
nerve," which he used to refer to as "the demon," 
or " number five." The attacks used to come on 
very suddenly, and again suddenly departed. In 
October he was kept in bed four days by a bad 
attack. He was unable to be present at the annual 
meeting of the Royal Society on November 30. 

On December 2 Lord Kelvin was admitted as 
an Honorary Member of the Philosophical Society 
of Glasgow, which he had joined as an ordinary 



member on December 2, 1846. An Address was 
presented to him, and at the same time a bronze 
bust of him was presented by a body of subscribers 
to the Society ; a duplicate bust being presented to 
Lady Kelvin. The same day there were unveiled, 
in the staircase of the University, two memorial 
tablets to Lord Sandford and to Professor Veitch. 
Lord Kelvin, who presided at this ceremony, gave 
recollections of his childhood, when Frank Sandford 
and he used to play in the old College Green, and 
make ships and sail them in the Molendinar Burn. 
On December 21, Lord Kelvin was in Edinburgh, 
communicating to the Royal Society of Edinburgh 
a paper on the Electrification of Air by Rontgen 
Rays. December 22 saw him in London, attending 
the opening, by the Prince of Wales, of the Davy- 
Faraday laboratories at the Royal Institution, en 
dowed by Dr. Ludwig Mond. 

After his Jubilee Lord Kelvin had resumed his 
University duties, and continued to experiment with 
unabated zeal. On January 13, 1897, he gave an 
evening public lecture at Glasgow University on 
the Molecular Dynamics of a Crystal ; and within 
a month read two papers dealing with crystalline 
forms to the Royal Society of Edinburgh. He 
gave several other papers to the same body on 
various subjects, including osmotic pressures, a 
subject in which he strongly opposed the views of 
Ostwald, writing to Lord Rayleigh several diatribes 
thereon. He was active, too, in other directions, 
taking part in the Jubilee of Queen s College, 


Belfast. He entertained Nansen when he visited 
Glasgow in February to lecture on his Polar travels, 
and presided at the lecture. 

Nature of March 25, 1897, contained a long 
and interesting illustrated article on Lord Kelvin s 
laboratory at the University, and on White s 
Instrument Factory, where Lord Kelvin s instru 
ments and compasses were made. James White, 
the original owner of the optical business, had died 
in 1884. His skill had been from the early days of 
the mirror galvanometer of great assistance to Lord 
Kelvin, who, when the manufacturing part of his 
works had increased, had found the capital needed 
for the business. The factory in Cambridge Street, 
Glasgow, built in 1884, employed about 200 hands, 
besides a staff of trained electrical engineers in the 
testing department. At this date the managing 
partner was Mr. David Reid, while Mr. James 
Ferguson looked after the electrical instruments ; 
but Lord Kelvin was daily about the works giving 
detailed instructions to workmen or foremen, and 
testing the adjustments of instruments and the fitting 
of the parts. His usual programme, when at home, 
was, after giving his secretary instructions about his 
correspondence, and, on certain mornings, lecturing 
to his class from 9 to 10, to walk or drive into the 
town to White s, often remaining there until time 
for a midday lecture, or for lunch. 

At this date appeared in Vanity Fair a rather 
cruel portrait of Lord Kelvin, accompanied by a 
terse but cordial appreciation. 


" He is so good a man," wrote the narrator, " that four 
years ago he was most deservedly ennobled as Baron Kelvin 
of Largs ; yet he is still full of wisdom, for his Peerage has 
not spoiled him. He is a very great, honest, and humble 
Scientist who has written much and done more. Yet, 
with all his greatness, he remains a very modest man of 
very charming manner." 

Lord Kelvin dined at the Royal Academy 
banquet on May ist. Replying for Science, he said 
he thought that if Raphael or Michael Angelo had 
seen a photograph they would have been both 
delighted and astonished. So much may be taken 
for granted, but whether they would, as he opined, 
have declared it to be "a masterpiece of art" is 
quite open to question. He aroused a ripple of 
laughter amongst the artists by telling them that 
they owed a debt of gratitude to the men of science 
who had proved to them that yellow and blue do 
not make green, but that green is unquestionably a 
primary sensation. 

On May 8 the Master of Peterhouse, Dr. Porter, 
who had been a student at Glasgow in 1846, under 
Lord Kelvin, was presented with a testimonial for 
his services to the University and town of Cam 
bridge ; and his portrait, painted by Ouless, was at 
the same time presented to the College. Lord 
Kelvin, as Senior Fellow of Peterhouse, received 
the portrait on behalf of the College, and spoke 
warmly of Dr. Porter, and of the efficiency that had 
marked his administration. 

It was at this time that a very determined, but 
unsuccessful attempt was made to induce the 


University of Cambridge to open its degrees to 
women. Girton and Newnham Colleges had now 
been in successful operation for twenty years ; and 
the promoters of the movement claimed that the 
University would now be justified in granting the 
titles of degrees to those women who were success 
ful in the Tripos examinations, which had long been 
open to them. The bulk of the resident members 
of the Senate were certainly opposed to this step. 
Lord Kelvin sided with the opponents, and became 
chairman of a London Committee of Cambridge 
graduates to resist the proposal. 

On May 21 Lord Kelvin gave a Friday evening 
discourse at the Royal Institution, on the Contact 
Electricity of Metals. He had worked actively at 
this subject forty years before, and had employed 
his electrometers to show the effect, discovered by 
Volta, of bringing copper and zinc into contact and 
then separating them, when they were found to be 
oppositely electrified. For many years a great con 
troversy had raged on the theory of the voltaic cell, 
some attributing its operation to contact, others 
(notably Faraday) to chemical action. Volta s experi- 
c ment had then been discredited until Lord Kelvin s 
electrometer experiments justified its truth. More 
recently electricians, while accepting the fact, had 
also sought to explain it as a chemical action. In 
the eighties there was considerable controversy 
as to this, Oliver Lodge maintaining that the 
so-called contact force, of about one volt, was due 
to the difference between the respective chemical 


affinities of the oxygen of the air for zinc and for 
copper. Lord Kelvin would never accept this idea, 
but attributed it to that affinity of zinc and copper 
for one another which is shown in their union to 
form brass. With that curious impenetrability to 
other men s ways of regarding things that was 
characteristic of Lord Kelvin s mind, he could never 
be brought to admit the cogency of Lodge s main 
proposition, 1 based as it was on the work which 
Lord Kelvin himself had done in collaboration with 
Joule in the fifties (see p. 401). He remained to 
the last unconvinced. Part of his Royal Institution 
lecture was directed to this point, and part to the 
effect of the Becquerel rays emitted by uranium in 
altering the apparent electrification due to contact. 

In the House of Lords, on May 28, 1897, Lord 
Kelvin spoke against the imposition of death duties 
upon works of art and collections of scientific instru 
ments or of objects of natural history, the property 
of private owners ; also private observatories, which 
had been of the greatest benefit to astronomy. He 
urged that in such cases the duty charged should 
be merely nominal. 

The Age of the Earth as an Abode fitted for 
Life was the subject of an address by Lord Kelvin 
to the Victoria Institute on June 2, 1897. In 
the Chapter on the Geological Controversy of 

1 The matter was further complicated by Lord Kelvin s method of defining 
the potential of a conductor as the potential of a point in the air infinitely 
close to its surface. This, as the present writer once pointed out in one of 
the discussions, leads to a fallacious conclusion ; for then the difference of 
potentials between copper and zinc in contact, if so defined, is quite different 
from the true difference of potentials between the metals themselves. 


the years 1862-1871 (see pages 535-551 supra), 
an account is given of Lord Kelvin s earlier argu 
ments; and on p. 941 is a brief notice of the revival 
of the question in 1895. He now reiterated his 
position in a reasoned address, which will be found 
in the Transactions of the Victoria Institute for 
1897, and is here summarized : 

He first recapitulated the old arguments against the Uniformi- 
tarian postulate of unlimited time; adding Sollas s recent estimate 
of 17,000,000 years as the outside limit of time elapsed since 
the beginning of the Cambrian epoch. He then referred to 
newer knowledge as to fusion and conductivity of rocks, which 
had narrowed his own earlier estimates down to something 
between 20 and 40 millions of years, and to Clarence King s 
independent estimate of 24 millions. Then, with a passing 
fling at British weights and measures, he discussed the bearing 
on the date of consolidation of the globe of recent measurements 
on the fusion and solidification of diabase, granite, and basalt. 
First, granite would crystallize out in a crust ; through the cracks 
in this an upper crust of basalt would extrude. When this 
oozing through cracks ceases, we have reached Leibnitz s con- 
sistentior status with surface cool and solid, and an internal 
temperature increasing to 1150 C. at 25, or 50, or 100 metres 
down. The main features of great continents would become 
fixed by the granitic formations in the lava ocean before its 
consolidation. After solidification was reached at the surface, 
cooling by radiation would continue. Condensation of vapours 
in the atmosphere would produce lakes, seas, and rivers. But to 
account for free oxygen in the air one must suppose vegetation 
to have begun ; and only a few thousands, or perhaps hundreds 
of thousands of years later would there be oxygen enough to 
support animal life as we now know it, unless, indeed, the earth s 
primitive atmosphere contained free oxygen. Certainly, if sun 
light were ready, the earth was ready both for vegetable and 
animal life within a few hundred centuries after the rocky con 
solidation of its surface. But was the sun ready ? According to 
the dynamical theory worked out by Helmholtz, Newcomb, and 
himself, the sun was probably ready only 20 to 25 millions of years 
ago. But to account for the commencement of life on the earth 
mathematics and dynamics fail us. We must pause, face to face 
with the mystery and miracle of the creation of living creatures. 



This was the last pronouncement of Lord Kelvin 
as to the age of the earth. But it is not the latest 
pronouncement of science. The discovery by Curie 
of the spontaneous evolution of heat from radium, 
and the detection by others of small quantities of 
radio-active materials in the crust of the earth, have 
added the knowledge of another internal source 
of heat. Sir George Darwin has put l the matter 
thus : 

The researches of Mr. Strutt on the radio-activity of rocks 
prove that we cannot regard the earth simply as a cooling globe ; 
and therefore Lord Kelvin s argument as to the age of the earth, 
as derived from the observed gradient of temperature, must be 
illusory. Indeed, even without regard to the initial temperature 
of the earth acquired by secular contraction, it is hard to under 
stand why the earth is not hotter inside than it is. ... The 
evidence, taken at its lowest, points to a period many times as 
great as was admitted by Lord Kelvin for the whole history of 
the solar system. 

And again : 2 

If we were still compelled to assent to the justice of Lord 
Kelvin s views as to the period of time which has elapsed since 
the earth solidified, and as to the age of the solar system, we 
should also have to admit that the theory of evolution under 
tidal influence is inapplicable to its full extent. . . . Lord Kelvin 
contended that the actual distribution of land and sea proves 
that the planet solidified at a time when the day had nearly its 
present length. . . . The calculations contained in paper 9, the 
plasticity of even the most refractory forms of matter under great 
stresses, and the contortions of geological strata, appear, to me 
at least, conclusive against Lord Kelvin s view. 

Sir George Darwin, whose researches on the 
dynamics of the globe contain frequent references 
to Lord Kelvin s researches, sums up the position 
by saying : " If I dissent from some of his views, I 

1 Scientific Papers > vol. ii., Preface, p. ix. 2 Ibid. p. vii. 


none the less regard him as amongst the greatest 
of those who have tried to guess the riddle of the 
history of the universe." 

A memorial subscription in honour of Sir John 
Fender resulted in a gift of ^5000 toward the 
endowment of the laboratory and chair of electrical 
engineering in University College, London. The 
presentation to the college was made on July 2, 
1897. Lord Kelvin, as a member of the Memorial 
Committee, alluded feelingly to the work done by 
Fender his lifelong friend for the success of the 
Atlantic cables of 1858, 1865, and 1866, and in 
afterwards founding the Eastern and the Eastern 
Extension Telegraph Companies. 

The sixtieth year of Queen Victoria s reign was 
celebrated on June 22, 1897, by a great procession 
through London to St. Paul s Cathedral. In that 
splendid and historic procession Lord Kelvin was 
assigned no place : science, art, literature, and 
learning were studiously ignored by the powers 
that be, in the organization of that vast demonstra 
tion of England s progress under her great Queen. 
He was present on board the White Star liner 
Teutonic to witness the Naval Review on June 
26th ; and as a peer was invited to attend the 
Military Review at Aldershot on July ist. 

On June 28th he opened the Shoreditch municipal 
electric lighting station, and praised the scheme for 
utilizing refuse in the dust destructor. On July 2nd 
he wrote to The Times warning the public against 
the dangers of the so-called " dry shampoo." On 


the 1 5th he formed one of a deputation from the 
Royal Society to present a congratulatory address 
to Queen Victoria at Windsor ; and on the 2Qth 
he visited the training ship H.M.S. Worcester, to 
which he presented one of his standard compasses. 

On August 4th he visited Greenock to open a 
carbon factory in connexion with the aluminium 
works at the Falls of Foyers. Some remarks which 
he made on this occasion evoked much comment : 

There was one splendid application of the electric furnace in 
Scotland at the Falls of Foyers. That magnificent piece of work 
of the Aluminium Company was the beginning of something that 
would yet transform the whole social economy of countries such 
as the Highlands, where water abounded. He looked forward to 
the time when the Highlands would be re-peopled to some degree 
with cultivators of the soil, but re-peopled also with industrious 
artizans doing the work which that utilization of the water would 
provide for them. The British Aluminium works were very 
popular in the locality. It was only at a distance that the 
sentimental question, " What is to become of the beautiful Falls 
of Foyers ? " was asked. They were going on now in all their 
beauty, and might go on so for many a year. He did not him 
self utter the aspiration that they might so go on. He thought 
when the time came that every drop of water that now fell over 
the Falls of Foyers was used for the benefit of mankind, no wise 
man, no man who thought of the good of the people, would 
regret that the power in the waterfall was developed for the 
benefit of mankind. 

Toronto was the meeting place of the British 
Association in 1897. Lord and Lady Kelvin sailed 
on August 7th on the Campania for New York, 
reaching Toronto on the i7th. At this meeting 
he read one paper, on the Fuel and Air Supply of 
the Earth. This discourse has never been printed 
in full. Its main theme was an estimate of the 
total probable amount of fuel on this planet. 

VOL. II 2 E 


Taking as a standard fuel one requiring three times its weight 
of oxygen to consume it, Lord Kelvin arrived at the conclusion 
that the total weight of fuel in the earth is not more than 340 
millions of millions of tons ; the uncombined oxygen over the 
globe being 1020 millions of millions of tons. The coal-supply 
of Great Britain was about one two-thousandth part of the total 
fuel supply of the world. Great Britain s coal was more than 
could possibly be burned by all the oxygen in the air immediately 
over the British Isles. In regard to the effect of sunlight in 
storing energy and fuel, the present rate of sunshine was equivalent 
to the production of two tons of vegetation per square metre, per 
thousand years ; an estimate agreeing very closely with the growth 
of German forests and of English hay-fields. We might, as coal 
fields become exhausted, have to think of growing hay for fuel, as 
more economical than raising coal. But if we burn up our fuel 
supplies so fast the oxygen of the air may become exhausted, and 
that exhaustion might come about in four or five centuries. 

The Times correspondent at Toronto wrote : 
" Lord Kelvin is above all others the popular 
favourite here ; he is received with acclamation 
wherever he appears." 

On his way to Toronto Lord Kelvin had visited 
Niagara Falls to see the huge industrial develop 
ment there arising, which he greatly praised in a 
statement which he gave to the press on his visit : 

The originators of the work so far carried out and now in 
progress, hold a concession for the development of 450,000 horse 
power from the Niagara waterfall. I do not myself believe that 
any such limit will be found to the use of this great natural source. 
I look forward to the time when the whole water from Lake Erie 
will find its way to the lower level of Lake Ontario through 
machinery, doing more good for the world than even that great 
benefit which we now possess in contemplation of the splendid 
scene which we have before us in the waterfall of Niagara. I 
wish I could live to see this grand development. I do not hope 
that our children s children will ever see the Niagara cataract. 
I look forward to a revival of life and prosperity in the Highlands 
of Scotland, and to the present crofters being succeeded by a 
happy industrial population occupied largely in manufactories 
rendered possible by the utilization of all the water power of the 


country. It seems to me a happy thought that the poor people 
of the country will be industrious artizans, rather than mere 
guides to tourists. 

In Toronto Lord Kelvin made several speeches 
on his university experiences, when he received 
an honorary degree from Toronto University ; on 
the benefits of the British Association, at the 
banquet given by the Governor-General of Canada ; 
and on other matters at several minor entertain 

After the meeting there was an excursion, lasting 
over a fortnight, across the Canadian continent, by 
the Canadian Pacific Railway, to Victoria, British 
Columbia. The party reached Winnipeg on 
August 28th, and crossed the prairies to Banff 
Hot Springs, through the Rockies to Laggan, Field, 
Glacier House, Revelstoke, and Vancouver. Lord 
Kelvin telegraphed home from Glacier House, 
" Have had splendid time. Most interesting and 
varied journey. Are enjoying ourselves immensely." 
A photograph, taken by Prof. E. M. Crookshank, 
representing Lord Kelvin standing beside the 
Kananaskis Fall, which is near the railway between 
Regina and Banff, is here reproduced as Plate XIV. 
Wherever he went, the popularity of his recep 
tion was universal and striking. Canadians gladly 
showed their appreciation not only of his position 
in the world of science, but of the service he had 
rendered Canada in connexion with the Atlantic 
telegraph. Returning by the Northern Pacific, they 
spent four days in the Yellowstone Park, and 


reached Chicago on September i5th. Thence by 
Pittsburg to New York, Long Island, and back to 
New York, whence Lord Kelvin paid a visit to 
Schenectady to see the General Electric Co. s 
works. Passing through Boston he went to Halifax, 
and on to Montreal to discuss water-power schemes, 
after which he spent a few days at Lennox with 
George Westinghouse. On October 1 1 he was in 
Philadelphia, visiting the University with Professor 
Barker ; running over to Princeton University ; 
joining in a discussion on " Matter " at the American 
Philosophical Society ; and enjoying social enter 
tainments. 1 On the 1 6th he sailed in the Campania ; 
and by the 2Qth he was in Cambridge for the 
statutory Meeting of Fellows at Peterhouse. 

The Rt. Hon. Joseph Chamberlain, as Lord 
Rector of the University, visited Glasgow on 
November 3rd, to deliver his Rectorial Address 2 
on " Patriotism," and stayed with Lord Kelvin. 

At the Watt anniversary, on January 23, 1898, 
Lord Kelvin spoke of the connection of James Watt 
with the University of Glasgow, and of the improve 
ments which he introduced into the steam-engine. 
Watt was a leader in science. He recalled how his 

1 An odd occurrence at a dinner party at the house of a gentleman whom 
for the purpose of biography we will call Mr. Frank Johnson, caused Lord 
and Lady Kelvin much amusement. A large company had been invited to 
dine at 7.30. Through some mishap their distinguished visitors were late, 
and the assembled guests and their hosts began to experience some uneasiness. 
Suddenly the draperies before the doorway were thrust aside, and in the open 
ing beamed the negro butler, who forthwith announced : " Mistah Johnson, 
de Lawd am come ! " 

2 The reporters record that whilst Mr. Chamberlain kept his eyeglass in 
his right eye all evening, Lord Kelvin, who wore his monocle in his left eye 
on entering, shifted it to his right eye during the latter part of the time. He 
had a favourite theory that the eyes should be rested alternately ! 


own great master in physical science, Regnault, had 
"la loi de Watt," the law of Watt as to the latent 
heat of steam, continually upon his lips. Even 
telegraphy owed something to Watt, for without the 
steam-engine and steam navigation they could never 
have had the ocean telegraphs. 

Lord Kelvin returned to thermodynamic studies 
in two papers read in February and March to the 
Royal Society of Edinburgh. The first related to 
the energy theory of volta-contact electricity, being 
an extension of the ideas put forward in his Royal 
Institution discourse of the previous year (see p. 996), 
with experiments conducted in a cycle of operations. 
The other was on thermodynamics founded on 
motivity, and in it he called attention to his paper 
of 1855 (see p. 294), in which he had laid down the 
doctrine of available energy. He also lectured 
to the Glasgow Philosophical Society on Mutual 
Actions between Plastic Solids and Liquids. About 
the same date he presented to the library of that 
Society a valuable collection of scientific books. 

At the graduation ceremony of April 12, 1898, 
owing to the illness of Principal Caird, the duty of 
presiding and presenting medals and prizes fell to 
Lord Kelvin as Senior Professor. After the cere 
mony he gave a brief address : 

Graduates and undergraduates, students, you have been busy 
for many months, or years, with your university studies. You 
have been creating property. You have not been making money, 
nor adding field to field, nor building houses. But you have 
been creating a property more precious than gold or silver, or 
broad acres, or houses that may be burned or ruined. The pro 
perty you have created is your very own for ever, indestructible, 


imperishable, inalienable. The splendid university organization, 
with its material resources, and the living influence of its teachers 
and students, has helped you. But every one of you has, by 
himself and for himself, by the power of God working in him, 
made the property which he brings away with him. May it to 
every one of you be a joy and a blessing for ever. 

Principal Caird died in July, and there was a 
rumour in the press that Lord Kelvin would be 
made Principal of the University. But it was 
known pretty generally that he would not accept 
the position ; and it appears that no actual offer of 
it to him was made, the Rev. R. H. Story being 
appointed to the post. 

Before that date Lord and Lady Kelvin had 
paid a visit to Hallam, Lord Tennyson, at Farring- 
ford, Freshwater. Thence Lord Kelvin wrote on 
June 3 to Darwin that he was still busy with revising 
the Baltimore Lectures. While staying at Farring- 
ford he went to see Signor Marconi s installation of 
wireless telegraphy between Alum Bay and Bourne 
mouth, and insisted on paying a shilling to send 
" through the ether" a message to Stokes. A week 
later he agreed to act as consulting engineer to the 
" Wireless Telegraph and Signal Company " about to 
be formed. Concerning this he wrote on June 1 2 : 

In accepting to be consulting engineer I am making a 
condition that no more money be asked from the public, 
for the present at all events ; as it seems to me that the 
present syndicate has as much capital as is needed for 
the work in prospect, and as could get a proper return 
out of earnings on applications which we can at present 
foresee. I am by no means confident that this condition 
will be acceptable to the promoters. But without it I 
cannot act. 


At intervals through this spring Lord Kelvin 
was giving sittings to Mr. (now Sir) W. Q. 
Orchardson for the portrait presented by subscrip 
tion to the Royal Society. His passion to fill up 
available moments is illustrated by the following 
note to Lord Rayleigh : 

PETERHOUSE LODGE, CAMB., May 22 [1898]. 

DEAR RAYLEIGH Stokes has been telling me of your 
investigation proving very extreme nullity of reflection of 
light at the polarizing angle (? very exactly Fresnel s ?) of 
water with the roughly pure surface. Will you give me 
the reference ? Will you come to Orchardson s on either 
Wed. or Friday next, or both, 1 1 to I o cl., so that we 
may have a good talk over many important affairs ? 
Yours, K. 

The Times of July 15, 1898, contained a short 
but cogent letter from Lord Kelvin on the Report 
of the Petroleum Committee (see p. 962). Mr. 
Jesse Collings, who had always opposed the much- 
needed reform of raising the flash-point test from 
the low value of 73 to 100, had rather foolishly 
written that if the oil flows out through the lamp 
breaking, " it matters little whether the oil is 73 or 
ioo." Lord Kelvin, who was scandalized by this 
officious defence of the use of cheap low flash-point 
oils, wrote, " I believe many lives will be saved 
by the adoption of the Committee s recommendation 
to prevent, as far as legislation can prevent, the use 
of oil for an illuminant with flash-point (Abel close 
test) below ioo." 

At the Bristol meeting of the British Association 
in September 1898, Lord Kelvin read three papers, 


two of them relating to the dynamics of the undula- 
tory theory of light, and one on the graphic re 
presentation of waves. 

Lord Kelvin took the chair on October 18, in 
St. Andrew s Hall, Glasgow, at a great Liberal 
Unionist meeting addressed by the Duke of Devon 
shire. Speaking as chairman, he described the 
Unionist alliance of 1886 as the greatest political 
event of the second half of the nineteenth century. 
He prophesied that this alliance would last on into 
the twentieth century, though the details of govern 
ment would be different, since history did not repeat 
itself. " I have," he said, " my ideas as to opposition 
and supporters of the Government : this is not the 
time to speak of them. But I do believe in a new 
mode of action in politics, in which everything shall 
be discussed according to its merits, and not accord 
ing to party ins and outs." 

In the ancient city of Colchester the annual 
Oyster Feast is usually made the occasion for 
inviting distinguished guests of honour. At the 
Oyster Feast 1 of October 31, 1898, the chief guests 
were H.R. H. the Duke of Cumberland, Lord 

1 Conviviality at this quaint civic festival never seems to be damped by 
the circumstance that the menu consists of unlimited oysters and brown bread 
and butter, all of primest quality ; and on this occasion the usual hilarity 
prevailed. In proposing the toast of Science and Engineering, Lord Claud 
Hamilton called upon Lord Kelvin, whose name was associated with the 
toast, to reply to the question : " Have you ever seen an oyster walk up 
stairs ? " Lord Kelvin said : No, he never had ; and he did not believe an 
oyster could walk upstairs. "But if," he said, "we adopt a theory at 
present very fashionable in modern science, the day will come when the 
oyster s great, great, great repeat it five hundred or five million times 
great grandson say a million million years hence will not only be able to 
walk upstairs, but also to attend the Oyster Feast, and when he arrives at the 
top will have to make a speech ! " 


Kelvin, Lord Rayleigh, the Lord Mayor of London, 
and Lord Claud Hamilton. 

Lord Kelvin attended the Annual Meeting and 
Banquet of the Royal Society on November 3Oth, 
but took no active part in the proceedings. He had 
been on 28th re-elected for the fifteenth time (with 
certain intervals between) President of the Royal 
Society of Edinburgh, an office which he held until 
his death. 

On January 13, 1899, Lord Kelvin paid a visit to 
Nottingham to see the electric lighting works. In 
February he was elected an honorary member of the 
Institution of Electrical Engineers, the first under 
the new rules of that body. 

He was still picking up the threads of his long- 
delayed publications, and wrote various notes about 
them to Lord Rayleigh, including the following : 

March 11/99. 

The Pitt Press have been profiting by my cold- 
prevention regime. They have been having a despatch 
of Baltimore every day, and must be arranging to engage 
fresh hands. 

I now, since yesterday evening, after a not sleepless 
night, believe undoubtingly the Green-Cauchy stress-theory 
of Double Refraction. K. 

Easter 1899 saw Lord and Lady Kelvin in Rome. 
Lord Kelvin was present on April 23 at the sitting 
of the R. Accademia dei Lincei, where he was 
welcomed by the President Sig. Beltrami in the 
following words : " I have the pleasure of announc 
ing to the Academy that this day s sitting is honoured 


by the presence of its venerated Foreign Associate 
Lord Kelvin, incomparably the most distinguished 
representative of physical science taken in its 
widest sense of our time in the whole civilized 
world." He then recounted Lord Kelvin s achieve 
ments, and invited the members of the Academy " to 
give a salute of honour to our venerated colleague, 
which they did by rising to their feet. On May i 
a complimentary banquet was given to Lord Kelvin 
by the Associazione Elettrotecnica Italiana and the 
Ministry of Posts and Telegraphs. Sig. Mengarini 
and three other speakers proposed the toast of his 
health in the warmest terms ; and Lord Kelvin in 
replying spoke with admiration of the extent to 
which electric engineering had been carried out in 
Rome. He had been deeply struck by the beauties 
of ancient Rome and the skill of her builders. Yet, 
he added, the old Romans, if they could come back 
to life, and see the transmission of 2000 horse-power 
by four wires no thicker than his little finger stretch 
ing across the Campagna to supply Rome with 
electricity from the cascade of Tivoli, along nearly 
the same route as their magnificent aqueducts, 
would think a feat had been accomplished even 
greater than those of old times. 

Returning northwards Lord and Lady Kelvin 
were entertained by the Batavian Society of Rotter 
dam on June 17. 

On June 26 Lord Kelvin spoke in the House of 
Lords against the insertion in mail-steamer contracts 
of clauses inflicting penalties for delay in arrival, 


irrespective of cause of delay. Such clauses were 
dangerous, as promoting high speed in times of fog. 
Later in the session he spoke against the Seats for 
Shop Girls Bill. 

He had now reached his seventy-fifth birthday. 
For some time he had determined on retiring from 
the duties of his professorship, and had been quietly 
preparing to withdraw from active service. At a 
meeting of the University Council on July n he 
presented a petition for leave to retire. The Council 
granted leave, and accepted his retirement with deep 
regret, instructing the Principal to prepare a minute 1 
to be signed by the members of the Court expressing 
their sense of the great loss the University was thus 
to sustain. His resignation took effect on October i, 
1899. In the autumn his former student and 
assistant, Andrew Gray, was chosen as his successor. 

Lord Kelvin had held the Chair of Natural 
Philosophy since 1846. "It was to him," said 
Principal Story, " an undisguised pain to sever the 
tie that bound him to the University." Yet the tie 
was not completely severed, for he insisted on in 
scribing his name on the University roll as a 
" research student." 

1 For the text of the minute and of Lord Kelvin s reply, see The Electrician, 
xliii. p. 689, September 8, 1899. 



Utinam caetera Naturae phaenomena ex principiis Mechanicis 
eodem argumentandi genere derivare liceret. Nam multa me movent 
ut nonnihil suspicer ea omnia ex viribus quibusdam pendere posse, 
quibus corporum particulae per causas nondum cognitas vel in se 
mutuo impelluntur et secundum figuras regulares cohaerent, vel ab 
invicem fugantur et recedunt : quibus viribus ignotis, Philosophi 
hactenus Naturam frustra tentarunt. Spero autem quod huic Philo- 
sophandi modo, vel veriori alicui, Principia hie posita lucem aliquam 
praebebunt. NEWTON, Philosophiae Naturalis Principia Mathe- 
matica (Praefatio ad Lectorem). 

SCIENCE is bound^ by the everlasting law of honour, 
to face fearlessly every problem that can fairly be 
presented to it. These were Lord Kelvin s words 
in 1871, in the Address (see p. 599) wherein he 
held out a prospect of the early completion of the 
molecular theory of matter " a great chart, in 
which all physical science will be represented with 
every property of matter shown in dynamical 
relation to the whole." For another quarter of a 
century he continued and nowhere more con 
spicuously than in the Baltimore Lectures to face 
fearlessly the outstanding problems of physics, the 
relation of ether to ponderable matter, the inner 
mechanism of the molecule, and the properties 


of electricity and magnetism which matter can 

If at his Jubilee his hearers were startled by the 
frank confession of " failure," it was no note of 
despair that he sounded. He himself told what he 
meant in a letter to M. Wilfrid de Fonvielle : 

July 25, 1896. 

DEAR MR. DE FONVIELLE ... I thank you 
also for the cutting from the Petit Journal which came 
to me from you a few days after your letter. I see 
in it a slight misunderstanding of what I said in 
Glasgow regarding " failure of my most strenuous 
efforts." It was not anything that I had been in the 
habit of teaching, either in my lectures or published 
papers, to which I referred. I am as firmly convinced as 
ever of the absolute truth of the kinetic theory of gases. 
What I feel that I have failed in has been my persevering 
efforts during 50 years to understand something more of 
the luminiferous ether and of the manner in which it is 
concerned in electric and magnetic forces ; and it was of 
this that I said I know no more now than I knew 
5 5 years ago when I became convinced that ether was 
essentially concerned in all these actions. Trusting you 
will kindly excuse my making this correction, I remain, 
yours very truly, KELVIN. 

He had, in fact, set before himself very early in 
his career an immensely high ideal, a noble ambition 
of so tremendous an import that it would seem as 
if all his life he had shrunk from exhibiting it in full 
panoply. Yet there had assuredly haunted him day 
by day the suggestion of an all-embracing, compre 
hensive theory of matter. In the Preface to 
Newton s Principia, the great philosopher after 
stating his claim to have deduced the motions of 


the Planets, the Comets, the Moon, and the Sea, 
by mathematical arguments, from the forces of 
gravity, uttered the aspiration : Utinam caetera 
Naturae phaenomena ex principiis Mechanicis eodem 
argumentandi genere derivare liceret. That pregnant 
sentence might well be the symbol of Lord Kelvin s 
intellectual career. 

That he worked often and strenuously at lesser 
aspects of the subject, that on occasions he deliber 
ately chose to explore some smaller region of the 
great " chart," is quite compatible with his holding 
the greater ambition as an ultimate aim. In the 
years of his boyhood the interconnexion of the 
physical sciences had been bit by bit revealed. 
Already Davy had discovered the chemical actions 
of the electric current, and Oersted and Arago 
its magnetic properties. Faraday had generated 
electric currents dynamically by the moving of a 
magnet ; and by a triumphant tour de force had 
proved magnetism to be capable of acting on light. 
Grove had drawn attention to the correlation of 
physical forces, a correlation not then amenable to 
calculation, and requiring the discovery of the great 
energy-principle to give the clue to the transforma 
tions so correlated. But the properties of matter, 
its ultimate structure, its elasticity and its compressi 
bility, its optical, electric, and magnetic qualities, 
these were as yet totally unexplained. They must 
be capable of explanation ; they must in some way 
depend upon the arrangement and mutual actions 
of the molecules of its structure, or upon the 


structure and properties of the molecules them 
selves, or upon their relation to the all-pervading 
ether of space. To be the Newton of the molecular 
theory which should afford a dynamical explanation 
of all these properties was a noble and worthy 

Such an idea seems to have come to William 
Thomson in a partial aspect during the spring of 
1846, while he was still at Peterhouse (see p. 159), 
when he was " often trying to connect the theory of 
propagation of electricity and magnetism with the 
solid transmission of force." But in the middle of 
composing the Inaugural Lecture of his Glasgow 
course in October 1846, the notion returned to him 
with compelling vividness, that he could somehow 
represent by the straining of an elastic solid the 
phenomena of electricity and magnetism. As his 
mathematical notebook shows (see p. 197), it 
was on 28th November 1846 that he at last suc 
ceeded in working out the " mechanico-cinematical " 
representation of electric, magnetic, and galvanic 
forces formulated in terms of the equations of an 
incompressible elastic solid. 

The paper, published in the Cambridge and 
Dublin Mathematical Journal for 1847, sets forth 
indeed a mechanical representation ; x but the 
theories it propounds are a mathematical skeleton 

1 It was this paper which started Maxwell s investigations. " The distinct 
conception of the possibility of the mathematical expressions arose in my 
mind from the perusal of Prof. W. Thomson s papers, On a Mechanical 
Representation of Electric, Magnetic, and Galvanic Forces, Cambridge 
and Dublin Mathematical Journal, January 1847, etc."; Maxwell, Camb. 
Phil. Trans. Dec. 10, 1855, P- 6 7- 


only, with no physical treatment such as with fuller 
powers he put forth in later life. He found, in 
fact, three particular solutions of the equations of 
equilibrium of an elastic solid. One of these, by 
mathematical analogy, expressed electric attractions 
as the result of an elastic displacement ; another 
expressed magnetic forces, statically, as the result 
of an angular displacement (not a sustained rota 
tional movement) ; the third, similarly, gave an 
elastic analogue for the forces in the neighbourhood 
of a wire carrying a current. He wound up by 
saying that a special examination of the various 
states of a solid body " must be reserved for a 
future paper." 

r . That the main proposition of this paper con 
stituted a mathematical analogy rather than a 
dynamical explanation Thomson was fully conscious : 
for, writing to Faraday about it in June 1847 
(see p. 203), he himself says that he did not 
venture even to hint at the possibility of making 
it the foundation of a physical theory of the pro 
pagation of electric and magnetic forces. He 
added, most significantly, that " if such a theory 
could be discovered, it would also, when taken in 
connexion with the undulatory theory of light, in 
all probability explain the effect of magnetism on 
polarized light." Obviously he had been trying to 
frame such a theory. 

Again and again, throughout his lectures and 
addresses, we meet with the phrase " the properties 
of matter." The Properties of Matter was the title 


assigned to a chapter alas ! never written of the 
great unfinished Treatise on Natural Philosophy. 
When, at an early date in his career, he was asked 
what was the object of a physical laboratory, he 
replied that it was " to investigate the properties of 
matter." Years afterwards, in the address called 
" Steps towards a Kinetic Theory of Matter," given 
in 1884 at Montreal, he said : 

. . . All the properties of matter are so connected 
that we can scarcely imagine one thoroughly explained 
without our seeing its relation to all the others, without in 
fact having the explanation of all, and till we have this 
we cannot tell what we mean by " explaining a property," 
or " explaining the properties " of matter. But though 
this consummation may never be reached by man, the 
progress of science may be, I believe will be, step by 
step towards it, on many different roads converging 
towards it from all sides. The kinetic theory of gases is, 
as I have said, a true step on one of the roads. Popular 
Lectures, vol. i. p. 233. 

His ideas as to the nature of matter were pro 
foundly influenced by the discoveries of Joule. 
From 1847 to J 855, when Thomson was working 
out his mathematical theory of magnetism (p. 211 
above), he had (as he stated in 1872 when com 
piling his reprint of Papers on Electrostatics and 
Magnetism] no belief in the reality of Ampere s 
theory, according to which magnetism of steel or 
iron consists of electric currents circulating round 
the molecules of the magnetized substance. In the 
note which he appended to p. 419 of that work, 
he confesses, " but I did not then know that motion 

VOL. II 2 F 


is the very essence of what has hitherto been 
called matter. At the 1847 meeting of the British 
^Association in Oxford, I learned from Joule the 
dynamical theory of heat, and was forced to abandon 
at once many, and gradually from year to year all 
other, statical preconceptions regarding the ultimate 
causes of apparently statical phenomena." 

Already in 1855 Thomson was speculating on 
the mechanical antecedents of motion, heat, and 
light, and had suggested that all of them originated 
in gravitation. And in his Royal Institution dis 
course of 1856 he suggested that all heat was 
electric, and all light also, although he gave no 
arguments in support of the suggestion. But in 
the same year he laid before the Royal Society 
certain dynamical illustrations of the rotatory effects 
of transparent bodies on polarized light. He had 
been considering Faraday s great discovery that 
magnetism acting on a piece of heavy-glass through 
which light is passing, can exert a turning effect on 
the plane of polarization of a beam of polarized light 
that is passing through it, and had compared that 
phenomenon with Arago s earlier discovery that 
in passing through a plate of quartz there is also 
a twisting of the plane of polarization. He now 
emphasized the essential difference between the 
two cases. If in the case of quartz the light is 
caused by reflexion to retraverse the quartz in the 
opposite direction, the rotation of the plane of 
polarization is annulled ; whereas in the case of 
the magnetized heavy-glass, on reflecting the light 


back through it the rotation is doubled. He there 
fore ascribed the action in the case of quartz to 
a spiral or helicoidal arrangement of the molecular 
structure ; and, in the case of the heavy-glass, to 
a real rotation impressed on the substance by the 
influence of the magnet. Not otherwise could one 
explain the circumstance that the rotatory effect in 
the magnetic case is independent of the "sense" of 
the propagation of the light through the substance. 
To make the matter plainer, he conceived certain 
dynamical models to show how the vibrations of 
material systems can be changed in azimuth by the 
influences of constraints and forces impressed upon 

From these illustrations it is easy to see in an infinite 
variety of ways how to make structures, homogeneous 
when considered on a large enough scale, which, with 
certain rotatory motions of component parts having, in 
portions large enough to be sensibly homogeneous, 
resultant axes of momenta arrayed like lines of magnetic 
force, shall have the dynamical property by which the optical 
phenomena of transparent bodies in the magnetic field are 
explained. Roy. Soc. Proc. viii. p. 155, June 1856. 

He had a word, too (ibid. p. 152), on the prob 
able relations between matter and ether : 

The introduction of the principle of moments of 
momenta into the mechanical treatment of Mr. Rankine s 
hypothesis of " molecular vortices " suggests the resultant 
moment of momenta of these motions as the definite 
measure of the " magnetic moment." The explanation 
of all phenomena of electromagnetic attraction or repul 
sion, and of electromagnetic induction, is to be looked 
for simply in the inertia and pressure of the matter of 


which the motions constitute heat. Whether this matter 
is or is not electricity, whether it is a continuous fluid 
interpermeating the spaces between molecular nuclei, or 
is itself molecularly grouped ; or whether all matter is 
continuous, and molecular heterogeneousness consists in 
finite vortical or other relative motions of contiguous 
parts of a body, it is impossible to decide, and perhaps 
in vain to speculate, in the present state of science. Ib. 
I p. 152. 

Occasionally he allowed himself to step forward 
beyond the bounds of the accepted philosophy, and 
to rush to intuitive conclusions for which afterwards 
he had to seek for logical demonstration. Witness 
the following passage 1 from the peroration to his 
Royal Institution discourse of May 1860 on Atmo 
spheric Electricity " : 

We now look on space as full. We know that light is 
propagated like sound through pressure and motion. . . . 
If electric force depends on a residual surface action, a 
resultant of an inner tension experienced by the insulating 
medium, we can conceive that electricity itself is to be 
understood as not an accident but an essence of matter. 
Whatever electricity is, it seems quite certain that electri 
city in motion IS heat ; and that a certain alignment of 
axes of revolution in this motion IS magnetism. Fara 
day s magneto-optic experiment makes this not a hypo- 
L thesis but a demonstrated conclusion. Thus a rifle-bullet 
keeps its point foremost ; Foucault s gyroscope finds the 
earth s axis of palpable rotation ; and the magnetic needle 
shows that more subtle rotatory movement in matter of 
the earth, which we call terrestrial magnetism : all by one 
and the same dynamical action. 

Two points in the above are worthy of note : 
the suggestion that electricity is an essential quality 

1 Electrostatics and Magnetism, pp. 224, 225. 


of matter, and that confident assertion that Faraday s 
experiment proves magnetism to be a dynamical 
phenomenon akin to the kinetic rigidity of rotation. 

It was at this stage that the writing of the 
Thomson and Tait Treatise came in to focus the 
conception that all the outlying branches of physics 
were essentially based on dynamics. And though 
in that great work the correlating notion avowedly 
put forward is that of the Conservation of Energy, 
yet it is dynamics, the science of the particular 
manifestation of energy when it is expended on 
moving masses, that dominates the treatment. 
What the oft-promised chapter on the " Properties of 
Matter" might have brought out in the way of ulti 
mate molecular theory cannot even be conjectured. 
But here and there some casual phrase reveals a 
thought, as, for example, in 340 (p. 275 of 
Vol. I.), where the authors speak of " the ultimate 
molecular motions constituting heat, light, and 

In October 1864 Clerk Maxwell published his 
famous Electromagnetic Theory of Light, in a paper 
read to the Royal Society of London. 1 Whether 
Thomson was present, or whether he made any 
comment at the time, is not known. What Maxwell 
propounded, if stated in the briefest possible terms, 
is this : that the propagation of light -waves may 
be explained by supposing that in a plane-polarized 
wave the minute transverse displacements of which 

1 Phil. Trans, civ. p. 459, " A Dynamical Theory of the Electro 
magnetic Field." 


the wave consists are not mechanical displacements 
but electrical ones, and that these are always accom 
panied by corresponding minute magnetic displace 
ments, also transverse, but at right angles to the 
electric displacements, half the energy in each wave 
being electrical and half magnetic ; the medium (the 
ether) being regarded as having a definite rigidity 
or electric elasticity (the reciprocal of its dielectric 
capacity), and as having also a definite inertia (an 
electromagnetic inertia due to self-induction). Pre 
cisely how Maxwell came to this view is not known. 
Probably it dawned upon him when considering the 
meaning of the ratio "v" (see p. 524), which Weber 
had shown to be the interconnecting relation between 
the electric and the magnetic units when reduced to 
an absolute basis. This velocity had been found by 
Weber to be 3- 1074 x io 10 cm. per second, being 
almost identical with that of light ; the best determi 
nations of which had given a velocity of 2-9992 x io 10 
cm. per second. Sir William Thomson, in March 
1868, had redetermined "z;," and found the slightly 
lower value of 2-825 x io 10 . According to Clerk 
Maxwell, " z; " bore the physical meaning of that 
velocity at which any sudden electromagnetic dis 
turbance would be propagated in transverse waves 
through free space. He himself had been studying 
such waves, though their actual existence was as yet 
unknown to experimenters ; and he laid down their 
equations on the theory of electric " displacement " 
in his memoir of 1864. If waves of light were 
observed to travel at the same particular speed at 


which electromagnetic waves were believed, from 
pure theory, to travel, might not lightwaves be 
electromagnetic in their essential nature ? For closer 
testing of this brilliant speculation Clerk Maxwell 
himself, in 1869, made a redetermination of the 
ratio "z/," and found it 2-8798 x io 10 cm. per second. 
But coincidence between the value of " v " and that 
of the velocity of light was not the only argument to 
support the theory. The opacity of all good electric 
conductors (except electrolytes) and the transparency 
of all dielectrics afforded an additional reason in 
favour of the theory. Moreover, if it were true, then 
the refractive index of any transparent medium 
should be proportional to the square root of its 
dielectric capacity. These things appeared to be 
broadly true, and Maxwell s pupils and disciples were 
for some years busy in examining the outstanding 

But Thomson, as mentioned on p. 879, would not 
bring himself to accept Maxwell s views. In the 
first place, he had in 1860 explicitly denied 1 that 
electricity as such had any definite velocity of 
travelling. He had shown in his early telegraphic 
investigations how the apparent velocity of propa 
gation of an electric impulse along a conducting line 
or cable is modified by the "embarrassment" due to 

1 Article on "Velocity of Electricity," Nicholas Cyclopedia (second edition), 
1860 ; "the supposed velocity of transmission of electric signals is not a 
definite constant like the velocity of light, even when one definite substance, 
copper, is the transmitting medium." 

It is, however, interesting to note that when reprinting this article in vol. 
ii. of his Math, and Phys. Papers, p. 137, in the year 1883, he added a 
reference to the chapter on the " Electromagnetic Theory of Light" in Maxwell s 


the charging of the surrounding dielectric (whether 
gutta - percha, air, or ether) ; and he was well 
acquainted with the inductive embarrassment met 
with in coiled circuits the retardation due to self- 
induction. It is true that Wheatstone, in 1834, had 
experimentally found the speed of propagation of a 
spark - discharge along copper wires to be 288,000 
miles per second, a speed distinctly greater than 
that of light, and that Fizeau and Gounelle, in 1850, 
had found the lower value of 112,000 miles per 
second. But Thomson s pronouncement of 1860 
shows that, up to that date at least, he had no 
confidence that electricity had any such intrinsic 
velocity. Moreover, he himself regarded Maxwell s 
theory as a backward step, hindering, not helping 
the attempt to find a true dynamical explanation of 
the propagation of light-waves ; or, as on a subse 
quent occasion he put it, 1 an attempt to explain 
^ignotum per ignotius. That he did not greet Clerk 
Maxwell s magnificent hypothesis with the en 
thusiasm with which it was acclaimed by the younger 
school of British physicists, is a fact not to be ignored 
or explained away. Nothing could be further from 
truth than the unworthy suggestion that he was 
jealous he who never throughout his whole career 
showed the least trace of any shadow of amoiir- 
propre in matters of scientific discovery of the fame 
of his younger compeer. Strict scrutiny of all the 
circumstances will show that the true explanation is 
quite other. He was a strong man, intellectually 

1 Baltimore Lectures, p. 271, in the passage quoted on p. 836 supra. 


strong, as we have seen in the matter of Carnot s 
theory, concerning which he had for three years 
held out against Joule s view, until he had been able 
to think out for himself the true scientific theory 
which brought both views together. So in the 
matter of Maxwell s theory he held tenaciously to 
his own way of regarding the fundamental relations 
between matter and motion, light and electricity ; 
and while not yet prepared to enunciate any com 
prehensive theory of his own, held back from 
accepting what seemed to him a partial if not 
retrograde hypothesis. There is probably also 
another reason. He once said (p. 827) that he 
was not satisfied with a formula unless he could 
feel its arithmetical magnitude ; at another time 
that he needed to interpret physically every 
line of a mathematical argument ; and yet again 
(p. 835), that no theory would satisfy him until 
he could imagine a model of it. He found himself 
unable to translate into a dynamical model the 
abstract equations of Maxwell s theory. It cannot 
even be said that he actually rejected Maxwell s 
theory : his own words sufficiently indicate his 
attitude of mind. In his Presidential Address of 
1871, in apparently his earliest comment on the 
subject, he spoke thus : 

Weber extended the practice of absolute measurement 
to electric currents. . . . He showed the relation between 
electrostatic and electromagnetic units for absolute 
measurement, and made the beautiful discovery that 
resistance, in absolute electromagnetic measure, and the 


reciprocal of resistance (or, as we call it, " conducting 
power ") in electrostatic measure, are each of them a 
velocity. He made an elaborate and difficult series of 
experiments to measure the velocity which is equal to the 
conducting power in electrostatic measure, and at the 
same time equal to the resistance in electromagnetic 
measure, in one and the same conductor. Maxwell, in 
making the first advance along a road of which Faraday 
was the pioneer, 1 discovered that this velocity is physically 
related to the velocity of light, and that, on a certain 
hypothesis regarding the elastic medium concerned, it may 
be exactly equal to the velocity of light. Weber s measure 
ment verifies approximately this equality, and stands in 
science monumentum aere perennius^ celebrated as having 
suggested this most grand theory, and as having afforded 
the first quantitative test of the recondite properties of 
matter on which the relations of electricity and light 
depend. A remeasurement of Weber s critical velocity 
on a new plan by Maxwell himself, and the important 
correction of the velocity of light by Foucault s laboratory 
experiments, verified by astronomical observation, seem 
to show a still closer agreement. The most accurate 
possible determination of Weber s critical velocity is just 
now a primary object of the Association s Committee 
on Electric Measurement ; and it is at present premature 
to speculate as to the closeness of the agreement between 
that velocity and the velocity of light. 

It will be remembered that in the years 1868 
to 1873 Thomson s students King, Dickson, and 
M Kichan had been set to work in his labora 
tory (p. 524) on a new determination of "z>," 

1 This may refer to Faraday s discovery of the magnetic rotation ot the 
plane of polarization of light, or it may possibly be a reference to Faraday s 
remarkable speculation of 1846, entitled "Thoughts on Ray- vibrations, 5 to 
which Maxwell in 1864 referred, saying, " The electromagnetic theory of 
light, as proposed by him (Faraday), is the same in substance as that which I 
have begun to develop in this paper, except that in 1846 there were no data 
to calculate the velocity of propagation " (Phil, Trans, civ. p. 466). 


and the result gave a value of 2-93 x io 10 cm. per 

But in the meantime Thomson had fallen upon 
Helmholtz s investigation of vortex motion, and had 
conceived the idea that in the vortex-ring, with its 
quasi-elasticity and its indestructibility (if formed in 
a frictionless fluid), we have the very type of the 
atom of matter : and he had himself (p. 517 supra) 
worked heart and soul at the vortex-atom theory. 
He had been searching for a reasonable basis for 
the kinetic theory of gases, and for exact data of the 
size, weight, and numbers of atoms, in the hope that 
the form and motion of the parts of each atom, and 
the distances separating them, might be calculated. 
He applauded the notion that the motions by which 
they produce heat, electricity, and light might be 
some day illustrated by exact geometric diagrams, 
and that the fundamental properties of the inter 
vening and possibly constituent medium might be 
arrived at. He suggested vortices of various forms, 
re - entrant, columnar, and tubular, to test their 
physical properties. Anything would be more satis 
factory than the incredible old idea of small spheres 
of infinite hardness and strength : they must be 
regarded as pieces of matter " of measurable dimen 
sions, with shape, motion, and laws of action." A 
theory of light which left out the atoms, and sought 
to explain the light-waves by calling them electro 
magnetic, seemed to him indeed inadequate, how 
ever grand. And indeed Maxwell s own statement 
of the theory was not without difficulty. It rested 


on a hypothesis concerning the elastic medium, of 
which he himself, in his great book on Electricity 
and Magnetism of 1873, was not able to give a very 
satisfying account ; and students of that work were 
greatly puzzled to attach any consistent physical 
meaning 1 to the conception of electrical " displace 
ment " which lay at the root of the matter. The 
fact is, that Maxwell s ideas also were in a state of 
flux, of which the abrupt transitions and gaps in his 
exposition remain to testify. Even now it is not 
possible to give a clear dynamical statement of that 
which he called displacement, except by reading 
into it the discoveries of recent years. Thomson s 
reserve was in entire accord with his temperamental 
bias toward freeing physical conceptions from unten 
able hypotheses. He was straining his faculties 
for a comprehensive molecular theory such as had 
never "been even imagined" before the nineteenth 
century ; and there could as he himself explicitly 
declared in 1871 be no permanent satisfaction 
to his mind in explaining heat, light, elasticity, 
diffusion, electricity, and magnetism, when the pro 
perties of the atom itself are simply assumed. The 
vortex theory was to him "a finger-post, 2 pointing a 

1 Maxwell s own statement in his paper in the Phil. Trans., 1864, p. 
462, runs thus : "In a dielectric under the action of electromotive force we 
may conceive that the electricity in each molecule is so displaced that one 
side is rendered positively and the other negatively electrified, but that the 
electricity remains entirely connected with the molecule, and does not pass 
from one molecule to another. The effect of this action on the whole 
dielectric mass is to produce a general displacement of electricity in a certain 
direction." The modern conception of the electron enables one to form a 
clearer view. 

2 On several occasions he used the simile of the finger-post to denote hints 
or possible hypotheses ; see pp. 885, 1031, and 1034. 



way which may possibly lead to a full understanding 
of the properties of atoms." 

In the same year, 1871, he discoursed to the 
Royal Society of Edinburgh on the ultramundane 
corpuscles by which Le Sage had proposed to ex- ; 
plain the existence of gravitation, and he connected 
with that theory certain propositions about the 
motion of rigid solids in a liquid circulating irrota- 
tionally through perforations in them, from which 
he deduced the gravitational law of inverse squares. 
After quoting Le Sage s propositions, Thomson 
remarks that this deduction would be " a per 
fectly obvious consequence of the assumptions 
were the gravific corpuscles sufficiently small." 
Then he continues (Proc. Roy. Soc. Edin. vii. 
p. 588) :- 

All that is necessary to complete Le Sage s theory of 
gravity, in accordance with modern science, is to assume 
that the ratio of the whole energy of the corpuscles to the 
translational part of their energy is greater, on the average, 
after collisions with mundane matter than after inter- 
collisions of any ultramundane corpuscles. This sugges 
tion is neither more nor less questionable than that of 
Clausius for gases, which is now admitted as one of the 
generally recognized truths of science. The corpuscular 
theory of gravity is no more difficult in allowance of its 
fundamental assumptions than the kinetic theory of gases 
as at present received ; and it is more complete, inasmuch 
as, from fundamental assumptions of an extremely simple 
character, it explains all the known phenomena of its 
subject, which cannot be said of the kinetic theory of gases 
so far as it has hitherto advanced. 

In 1872 he returned to a favourite hydrokinetic 


analogy 1 of 1847, in which he had shown that the 
velocity of fluid along its stream lines may represent 
from point to point the magnetic forces produced by 
a system of electric currents distributed on a surface. 

In 1875, while under the spell of his gyrostatic 
studies, he investigated the effect of rotating masses 
on the properties of any mechanical system in which 
they might form a part, studying, for example, the 
propagation of waves along a stretched uniform 
chain of gyrostats ; doubtless bearing in mind all 
the while the possible explanation it might afford of 
elasticity in general, or of the propagation of mag 
netic waves through a medium containing magnetic 

His next pronouncement on Maxwell s theory 
was in his South Kensington address (see p. 668) on 
" Electrical Measurement" : 

. . . Professor Clerk Maxwell gave a theory leading 
towards a dynamical theory of magnetism, part of which 
suggested to him that the velocity for which the one 
measure is equal to the other, in the manner I have 
explained, should be the velocity of light. This brilliant 
suggestion has attracted great attention, and has become 
an object of intense interest, not merely for the sake of 
accurate electromagnetic and electrostatic measuring 
the measuring with great accuracy the relation between 
electrostatic and electromagnetic units but also in con 
nection with physical theory. It seems, up to the present 
time, that the more accurate such an experiment becomes, 
the more nearly does the result approach to being equal 
to the velocity of light, but still we must hold opinion in 
reserve before we can say that. The result has to be 

1 See p. 206, his paper on the Electric Currents by which the Phenomena 
of Terrestrial Magnetism may be produced. 


much closer than has been shown by the experiments 
already made before the suggestion can be accepted. 
Popular Lectures, vol. i. pp. 442-443. 

His Royal Institution discourse of March 1881 
(see p. 743), when he exhibited his experiments on 
the quasi -elasticity of rotating systems, gave him 
occasion to remark how distant seemed the prospect 
of any such great comprehensive theory as that he 

. . . May not the elasticity of every ultimate atom of 
matter be thus explained ? But this kinetic theory of 
matter is a dream, and can be nothing else, until it can 
explain chemical affinity, electricity, magnetism, gravita 
tion, and the inertia of masses (that is, crowds) of vortices. 

Le Sage s theory might give an explanation of gravity 
and of its relation to inertia of masses, on the vortex 
theory, were it not for the essential aeolotropy of crystals, 
and the seemingly perfect isotropy of gravity. No finger 
post pointing towards a way that can possibly lead to a 
surmounting of this difficulty, or a turning of its flank, 
has been discovered, or imagined as discoverable. Belief 
that no other theory of matter is possible is the only 
ground for anticipating that there is in store for the world 
another beautiful book to be called Elasticity, a Mode of 
Motion. Popular Lectures, vol. i. p. 145. 

When in 1883 Thomson was lecturing on the 
size of atoms at the Royal Institution he touched 
upon the argument afforded by the dispersion of 
light in refracting media, such as glass or water, 
that the molecular structure cannot be infinitely 
small compared with the wave-lengths of light, an 
argument which Cauchy first enunciated as a 
dynamical theory of the prismatic colours. This 
theory he had examined and found inadequate to 


explain the large amount of dispersion actually 
observed in carbon bisulphide and in dense flint 
glass. Early in the very morning of his lecture he 
conceived another explanation the same which he 
afterwards amplified in the Baltimore Lectures (see 

P . 8i 7 ):- 

We must then find another explanation of dispersion ; 
and I believe there is another explanation. I believe 
that, while giving up Cauchy s unmodified theory of dis 
persion, we shall find that the same general principle is 
applicable, and that by imagining each molecule to be 
loaded in a certain definite way by elastic connection 
with heavier matter each molecule of the ether to have, 
in palpable transparent matter, a small fringe so to speak 
of particles, larger and larger in their successive order, 
elastically connected with it we shall have a rude 
mechanical explanation, realisable by the notably easy 
addition of the proper appliances to the dynamical models 
before you, to account for refractive dispersion in an 
infinitely fine-grained structure. It is not seventeen 
hours since I saw the possibility of this explanation. I 
think I now see it perfectly, but you will excuse my not 
going into the theory more fully under the circumstances. 
Popular Lectures, vol. i. pp. 194-195. 

He gave a mathematical account of this dynami 
cal theory * of dispersion a month later to the Royal 
Society of Edinburgh. 

" Steps toward a Kinetic Theory of Matter " was 
the title of Sir William Thomson s Montreal 
address in 1884. This was largely an account of 
the kinetic theory of gases, as developed up to that 
date, and in the course of it he touched on the 

1 It is substantially the same as that outlined by Sellmeier (Pogg. Ann. 
cxliii. 1872), and extended by Helmholtz (ibid. cliv. 1875). 


difficulty arising as soon as one began to consider 
what happened during the collision or impact 
between two molecules of a gas. In any attempt to 
realise a conception of the kinetic theory, one cannot 
evade a question as to the nature of the force during 
an impact. 

. . . And in fact, unless we are satisfied to imagine 
the atoms of a gas as mathematical points endowed with 
inertia, and as, according to Boscovich, endowed with 
forces of mutual positive and negative attraction, varying 
according to some definite function of the distance, we 
cannot avoid the question of impacts, and of vibrations 
and rotations of the molecules resulting from impacts, 
and we must look distinctly on each molecule as being 
either a little elastic solid, or a configuration of motion in 
a continuous all-pervading liquid. I do not myself see 
how we can ever permanently rest anywhere short of this 
last view ; but it would be a very pleasant temporary 
resting-place on the way to it, if we could, as it were, 
make a mechanical model of a gas out of little pieces of 
round, perfectly elastic solid matter, flying about through 
the space occupied by the gas, and colliding with one 
another, and against the sides of the containing vessel. 
This is, in fact, all we have of kinetic theory of gases up 
to the present time, and this has done for us, in the 
hands of Clausius and Maxwell, the great things which 
constitute our first step towards a molecular theory of 
matter. Of course from it we should have to go on to 
find an explanation of the elasticity and all the other 
properties of the molecules themselves, a subject vastly 
more complex and difficult than the gaseous properties 
for the explanation of which we assume the elastic 
molecule ; but without any explanation of the properties of 
the molecule itself. Popular Lectures, vol. i. pp. 228-229. 

But a more serious difficulty, which he had to 
leave unsolved, was the certainty he thought it 

VOL. II 2 G 


" rigorously demonstrable " that the whole of the 
translational energy of the flying molecules, if each 
is a continuous elastic solid, must ultimately be 
frittered down into vibrational energy, and therefore 
become lost by radiation. So he turned to the 
question of elasticity. 

If we could make out of matter devoid of elasticity a 
combined system of relatively moving parts which, in 
virtue of motion, has the essential characteristics of an 
elastic body, this would surely be, if not positively a step 
in the kinetic theory of matter, at least a finger-post point 
ing a way which we may hope will lead to a kinetic 
theory of matter. Ibid. i. p. 235. 

This, he continued, we can do in several ways. 
And he here referred to his own published papers 
on vortex atoms, and on elasticity as possibly a 
mode of motion (see p. 743), and to his model 
spring-balance containing gyrostats (p. 745), and to 
his model medium imitating the luminiferous ether, 
built up with portions possessing kinetic stability, 
due either to gyrostats or to inviscid fluids with 
" irrotational circulation " through the pores of 
solids. He imagined in this way a model vortex 
gas, and another hydrokinetic model composed of 
vortices in a pure liquid. In the latter case the 
difficulty about impacts disappeared ; and, more 
over, so far as he was then able to ascertain 
concerning the vibration of vortices, there no longer 
seemed any danger of the translational or impulsive 
energies of the individual vortices becoming lost 
or frittered away in energy of smaller and smaller 


The lecture on the Wave Theory of Light, which 
Sir William Thomson delivered in Philadelphia on his 
way to Baltimore, abounds in hints and references 
to the dynamical explanation of the properties of 
matter. A few isolated extracts must here suffice. 
He was concerned with the relation between the 
luminiferous ether and the molecules embedded 
in it. 

. . . You can imagine particles of something, the 
thing whose motion constitutes light. This thing we call 
the luminiferous ether. That is the only substance we are 
confident of in dynamics. One thing we are sure of, and 
that is the reality and substantiality of the luminiferous 
ether. . . . Popular Lectures^ vol. i. p. 31 o. 

. . . So when we explain the nature of electricity, we 
explain it by a motion of the luminiferous ether. We 
cannot say that it is electricity. What can this lumini 
ferous ether be ? It is something that the planets move 
through with the greatest ease. . . . Ibid. p. 327. 

. . . The fundamental question as to whether or not 
luminiferous ether has gravity has not been answered. 
We have no knowledge that the luminiferous ether is 
attracted by gravity ; it is sometimes called imponderable, 
because some people vainly imagine that it has no weight. 
I call it matter with the same kind of rigidity that this 
elastic jelly has. Ibid. p. 329. 

In Chapter XX., on the Baltimore Lectures, 
p. 835 above, the passage has been cited in which 
Lord Kelvin gave as a reason why he could not 
accept the electromagnetic theory of light, that he 
could not make a model of it. But a probably more 
important reason was that Maxwell s theory was 
essentially molar, not molecular, 1 and did not touch 

1 Maxwell, in his Treatise^ 260, vol. i. p. 312, once indeed uses the phrase, 
" one molecule of electricity," but immediately excuses himself for this lapse 


molecular questions, which Lord Kelvin deemed 
absolutely fundamental. Maxwell had assumed that 
the mechanical and molecular properties of a 
material system are independent of one another, 
and capable of being separately regarded ; this Lord 
Kelvin implicitly denied. And so he went his own 
way, striving to find other explanations, other modes 
of handling the problem of the propagation of light 
which should be essentially founded l on molecular 
dynamics. But it can scarcely be denied that these 
lectures give the reader the impression of a powerful 
mind struggling with its own convictions, and 
hampered by not finding the solution which he was 
convinced would be ultimately triumphant. No 
sooner were the lectures delivered than he began to 
work at supplements to them, and to revise them 
for a definitive publication. 

The first fifteen lectures were not materially 
altered in the revision, though portions were trans 
ferred to them from the later lectures ; but from 
Lecture XVI. to the end they were almost entirely 
rewritten in the years 1901 to 1903, and their 
paragraphs numbered consecutively from this point 
onwards. In Lecture XVII. he quoted from his 
1 870 article on the size of atoms (p. 566), a difficulty 
then felt in the kinetic theory of gases, as to the 

by adding : " This phrase, gross as it is, and out of harmony -with the rest of 
this treatise, will enable us at least to state clearly what is known about 
electrolysis." The words here italicized amply justify were justification 
needed the reserve which Lord Kelvin felt and expressed. 

1 " It is absolutely certain," he said in Lecture XII., that there is a 
definite dynamical theory for waves of light, to be enriched, not abolished, by 
electromagnetic theory. Baltimore Lectures (1904), p. 159. 


hard and fast demarcation between infinite force 
between the atoms when in contact, and zero force 
when not in contact, arising from the assumption 
of rigid, inelastic atoms. This hypothesis had 
seemed to require mitigation. He now wrote that 
Boscovich s theory clearly supplies the needed miti 
gation, and proceeded to explain the " Boscovich 
atoms," which exercise a mutual repulsion at small 
distances between centres, and an attraction when 
distances between centres exceed a definite limit. 
Lecture XVIII., as revised, was devoted wholly 
to the reflexion of light, and to the difficulty of 
accounting, by the theories of Fresnel and of Green, 
for the almost perfect extinction of polarized light 
when reflected at the critical angle. He referred to 
his own research of 1888 (p. 872), in which he 
found that a medium resembling a homogeneous 
airless foam, held from collapse by adhesion to a 
containing vessel, would possess a definite rigidity 
and elasticity of form, and a definite velocity of 
distortional wave, while fulfilling the condition that 
had puzzled him so much in 1884 of having a zero 
velocity for any compressional wave. The difficulty 
of accounting for metallic and adamantine reflexion, 
and the mathematical artifice for meeting that 
difficulty, are considered at length. In Lecture 
XIX. the reconciliation of the theory of Fresnel 
with that of Green is effected, by accepting, in order 
to explain double-refraction, the hypothesis that the 
inertia of a crystal may be aeolotropic, that is, have 
different values in different directions. Lecture 


XX. was entirely reconstructed by the introduction 
of his own newer conceptions as to atoms and ether 
occupying the same space at the same time, and 
as to electric forces within the molecule, as will 
presently be seen. 

The difficulty which Lord Kelvin felt respecting 
Maxwell s doctrine of dielectric " displacement " was 
frequently mentioned by him. It is referred to in 
the following letter to FitzGerald, who in March 
1885 had suggested to the Physical Society a 
dynamical model of an " ether," in which it was 
proposed to represent an electrical displacement by 
a change of structure, and not by a mere shifting of 
an element of the medium. 

April, 1885. 

DEAR FITZGERALD . . . Any one reading your paper 
as it stands would imagine that I had ignored a definite 
velocity of propagation for electric impulses. How wrong 
this inference would be is illustrated by p. 134 line 9 
from foot. I think in any case you ought to add to 
what you have already quoted from my paper,- the last 
sentence of page 134 and the first of page 135 contain 
ing my reference to Kirchhofif. 

I have never yet felt any satisfaction in Maxwell s 
783, 784, 790, 79i, 792, 645, 646, 794, 797, 798, 
824 . . . 829. I have never yet met anyone who under 
stood a definite dynamical foundation for 783. 

Is there any chance of your being in London or 
Cambridge during May? We are to be in London for 
about the first half of the month, and in Cambridge 
staying with the Stokes s probably during Whitsun week. 
I shall be very glad if we have an opportunity of meet 
ing so as to fight or agree relatively to the waves of light. 
Believe me, yours very truly, 



In 1887 Sir William Thomson himself enunciated 
a Vortex Theory of Luminiferous Ether, 1 in which 
he gave pictures of assemblages of vortex-rings to 
show how they would resist distortion, and so serve 
as a medium for the propagation of waves. His 
aim was " to construct by given vortex-motion of an 
incompressible inviscid liquid, a medium which shall 
transmit waves of laminar motion as the luminiferous 
ether transmits waves of light." 

In the summer of 1888, while revising the 
Baltimore Lectures, Sir William was still perplexed 
and haunted by the difficulty of finding an explana 
tion for the propagation of electrostatic forces. His 
difficulty appears in a post-card which he addressed 
to Lord Rayleigh on August 12, 1888, from Glas 
gow, where he had gone on the occasion of a visit 
of Queen Victoria. 


Aug. 22. 

Given two conducting globes oppositely charged (equal 
quant y ) in blue sky. Let the blue suddenly become con 
ductive ; say as conductive as slate or as ^__^^^ 
marble. The discharge will be along the fi "V 

lines of the previous electrostatic force, and [ j 

e -^ 2 / w iH be the time law of subsidence, it ( } 

being slow enough for no quasi-inertia. 
Where are the " displacement " currents and where the 
possibility of expressing the result (with or without 
quasi-inertia) by any even pseudo circuits, or imagined 
analogues of incomplete circuits ? Alas alas, the whole 
thing breaks down the first time it is really put on trial. 
H. Lamb did find it to fail for such an elementary thing 
as elect 7 flowing to equil m , but did not notice that this 

1 Brit. Assoc. Report, 1887 ; PhiJos. Magazine, Oct. 1887, . . . 


failure shows that the formulas he quoted in the beginning 
are not " the equa ns of electromag induction." He also 
(p. 523, 11. 5 and 6 from foot) found 2 + 2^4, and 
this peculiarity of Maxwell s has been pointed out by 
C. Niven." W. T. 

It is, however, possible to frame an explanation 
of the case in accordance with Maxwell s theory, 
since the subsidence of the electric field will not in 
volve any quasi-inertia, except perhaps inter-mole 
cular, of which Maxwell s theory takes no cognisance. 

A fortnight later came the British Association 
meeting at Bath, where, in the Physical Section 
under Professor FitzGerald, there was a great dis 
cussion upon electromagnetic matters. Within the 
preceding twelve months Hertz had published the 
classical researches on electric waves by which he 
had experimentally realized that which was essen 
tially true in Maxwell s doctrine ; and had shown 
that electric waves can be reflected and refracted 
exactly as light waves can, and that they travel at 
the same speed. Rowland of Baltimore was present, 
and Oliver Lodge (now Sir Oliver). Sir William 
Thomson was announced to give two papers, one 
of which at least was directed to electromagnetic 
questions. He also had, in conjunction with 
Professors Ayrton and Perry, prepared a new 
determination 1 of the ratio " v." 

An excellent account of this discussion was 
written by Lodge for The Electrician (vol. xxi. 

1 Compare pp. 524 and 1022. The result now obtained from measurements 
of the capacity of a condenser was 2-93 x io 10 cm. per second. Rowland 
by a kindred method had found 2-995 x io 10 . 


p. 622, Sept. 21, 1888), from which it appears that, 
without abandoning the solid-elastic theory of light 
(which in some form or other seems a necessity), 
Sir William Thomson was assimilating, while still 
criticizing, Maxwell s theory, and rejecting certain 
of its excrescences. The main point under dis 
cussion related to the mode and rate of propagation 
of electrostatic potential as compared with electro 
magnetic potential. Lodge s interesting report con 
tains the following passage : 

. . . On the last day of the meeting Rowland and Fitz- 
Gerald seemed to come to an understanding, but whether 
Sir William will coincide with it, or will upset the whole 
thing once more, remains to be seen. As they put it the 
matter is now like this : The propagation of electrostatic 
potential does not go on by end-thrust at all ; it is not 
really analogous to a pulse of longitudinal compression, 
though it is apparently and superficially so ; and accord 
ingly its rate of propagation depends not at all on the 
compressibility or incompressibility of the ether, a question 
on which it has nothing to say one way or the other. An 
electrostatic field is not developed sui generis, but is always 
the consequence of a previously existing electromagnetic 
one, which, on subsiding, leaves it as its permanent record. 

Plainly an electrostatic field cannot arise without the 
motion of some electricity, either with or through a con 
ductor. Now, whenever electricity moves it at once has 
magnetic properties its motion generates a magnetic 
field. When the motion ceases the field at once subsides, 
and in subsiding it may produce a succession of diffusing 
and dying away induction currents in neighbouring con 
ductors ; or it may, if the circuit be an incomplete one, 
leave a permanent vestige of itself in the dielectric as a 
field of strained ether this state of strain being what we 
call electrostatic potential, and the field being familiar to 
us as an electrostatic field. 


f Generating it 1 in this way, all distinction between rate 

of propagation of electrostatic and electromagnetic 

^ y potential vanishes, they both travel together with the 

{ r> ^ velocity of light ; or rather, the thing which travels is the 

magnetic potential, and its permanent effect in situ is the 

v electrostatic potential. 

Thus, once more, the difficulty of a longitudinal or 
pressural wave disappears from the electrical theory of 
light, into which it had seemed to intrude itself, and ^r is 
left to enjoy " a long and useful career," though it is not 
permitted an infinite or any other rate of propagation in 
its own proper nature. If any one asks how soon will 
the pull of a suddenly electrified body be felt at a 
distance? one may answer, "As soon as the charging 
spark is seen." But if it be asked at what rate electro 
static potential travels, the answer is that it does not 
travel, but is generated in situ by the subsidence of a 
magnetic potential which travels with the velocity of light. 

In November 1888, Sir William communicated 
to the Philosophical Magazine a paper " On the 
Reflexion and Refraction of Light," in which once 
more he returned to Green s solid-elastic theory, 
endeavouring to argue backwards from the facts of 
the propagation of polarized light to the physical 
properties which a medium must possess in order to 
account for the known facts. This important paper 
has never been reprinted. 

As told on p. 88 1, Sir William undertook the 
duties of President of the Institution of Electrical 

1 I.e. an electrostatic field. Sir Oliver Lodge informs the author that he 
would now (1909) restate the matter somewhat in the following way : Of the 
three vectors at right angles to one another electric force, magnetic force, 
and motion the superposition of any two necessarily involves the third. 
Given, therefore, electric and magnetic induction, motion at once follows, and 
the wave spreads out with the speed of light. A wave is generated by every 
electric acceleration, and therefore by a separation of electric charges. 
Whether any permanent result is left in the region over which the wave has 
travelled, depends upon whether the electric separation is permanent or not. 


Engineers for the year 1889, and wrote to the 
Secretary of that body as follows : 

4//fc Jany. 1889. 

DEAR MR. WEBB I am sorry it will be impossible 
for me to have anything of my presidential address in 
writing. The scientific subject upon which I propose to 
speak is " Electricity, Ether, and Ponderable Matter," 
and I hope to show one or at the most two very simple 
experiments with my gyrostats to illustrate rotating mole 
cules in connection with dynamical theory for magnetism. 
But I shall have to state very strongly that the difficulties 
in the way of proving a comprehensive dynamical theory 
of electricity, magnetism, and light are quite stupendous ; 
and that in the present state of science the imagination 
is absolutely baffled in attempts to give a mechanical 
foundation for explaining great laws of nature on which 
the work of the electrical engineer depends. 

I shall call about 1 1 o clock on Thursday to arrange 
about the experiments, for which very little of apparatus, 
beyond the gyrostats which I shall bring with me, will be 
wanted. Perhaps one of your young men might be able 
to assist me in preparing the experiments during the 
course of the lecture. Whatever record of the address is 
wanted will depend solely on the short-hand writer. 

I should be much obliged by your letting me have in 
the course of a day or two any statement which it is 
desirable I should read with reference to the Society 
under its late title, and with reference to its future exist 
ence under the more appropriately comprehensive name 
now chosen for it. 

Reciprocating heartily your kind wishes for a Happy New 
Year. I remain, yours truly, WILLIAM THOMSON. 

There are several salient features in this address. 1 
In one of these he touched on the velocity "z;," in 
the following words : 

1 Journal of Institution of Electrical Engineers, vol. xviii. p. 4, 1889 ; 
partly reprinted in Math, and Phys. Papers, vol. iii. p. 484. 


But its relationship to the velocity of light was brought 
out in a manner by Maxwell to make it part of a theory, 
which it never was before. Maxwell pointed out its 
application to the possible or probable explanation of 
electric effects by the influence of a medium, and showed 
that that medium the medium whose motions constitute 
light must be ether. Maxwell s "electromagnetic 
theory of light " marks a stage of enormous importance 
in electromagnetic doctrine, and I cannot doubt but that 
in electromagnetic practice we shall derive great benefit 
from a pursuing of the theoretical ideas suggested by such 
considerations. Math, and Phys. Papers, vol. iii. 490. 

Then he returned to the solid-elastic theory that 
had occupied his thoughts in 1846 (p. 197), and to 
the difficulty he had found in the forty-two years 
that had since gone by, in finding any further ex 
planation. He touched on his recent hydrokinetic 
model of the porous elastic solid of small density 
having its pores filled with a dense viscous fluid 
circulating through it, which would realize dynami 
cally the problems of electromagnetic induction, 
provided that nothing but electricity and ether had 
to be accounted for. But ponderable matter must 
be considered also, and there was the mystery that 
solid bodies could move freely through the ether. 
So he proceeded to describe an imaginary model 
ether or medium which should be absolutely mobile 
to translational movements, and yet possess rota 
tional rigidity. To this end he imagined a sort of 
network, across the meshes of which were set minute 
gyrostats spinning each about its own axis, to give 
the structure the necessary immobility. 

Thus we have a skeleton model of a special elastic 


solid, with a structure essentially involving a gyrostatic 
contribution to rigidity. Now do not imagine that a 
structure of this kind, gross as it is, is necessarily un- 
instructive. Look at the structures of living things ; 
think of all we have to explain in electricity and magnet 
ism ; and allow, at least, that there must be some kind 
of structure in the ultimate molecules of conductors, non 
conductors, magnetic bodies, and non-magnetic bodies, by 
which their wonderful properties now known to us, but 
not explained, are to be explained. We cannot suppose 
all dead matter to be without form or void, and without 
any structure ; its molecules must have some shape ; they 
must have some relation to one another. 

So that I do not admit that it is merely playing at 
theory, but it is helping our minds to think of possi 
bilities, if by a model, however rough and impracticable, 
we show that a structure can be produced which is an 
incompressible frictionless liquid when no gyrostatic 
arrangement is in it, and which acquires a peculiar 
rotational elasticity or rigidity as the effect of introducing 
the gyrostats into these squares (ibid. p. 508). 

In brief, he had abandoned the solid-elastic theory, 
and substituted a new one, in which he figured to 
himself a mathematical ether not corresponding to 
any known physical material, which derived its 
properties from concealed internal rotations, and 
which, while absolutely labile, in the sense that it 
was incapable of propagating a compressional wave, 
possessed a torsional rigidity. This in fact corre 
sponded exactly l to the optical ether suggested in 

1 That MacCullagh s equations for the reflexion and refraction of light 
may be interpreted on the supposition that what is resisted is not deformation 
but rotation, was shown by FitzGerald in 1880, and more fully developed by 
Larmor in 1893 in his great paper, " A Dynamical Theory of the Electric and 
Luminiferous Medium," in the Phil. Trans, vol. clxxxv. (Series A), p. 723 ; 
wherein also it is shown that at any point in the medium electrical displace 
ment in the electromagnetic theory corresponds to absolute rotation on 
MacCullagh s theory, and magnetic force corresponds similarly to velocity. 


1829 by MacCullagh, and advocated in 1850 by 
Rankine, but rejected at the time precisely because 
it did not behave as an elastic solid. This new 
hypothesis he expanded in 1889 in papers read to 
the Academic des Sciences and to the Royal Society 
of Edinburgh, " On a Gyrostatic Adynamic Consti 
tution for Ether." 

But even this brilliant suggestion did not satisfy 
Sir William Thomson. He had turned the optical 
difficulty and had reconciled Green and Fresnel with 
truth ; but the existence of electrostatic force was 
still unexplained, likewise the mutual attraction 
between the iron of an electromagnet and its keeper ; 
nor had he solved the puzzle that the ether must 
permit solid bodies to move with perfect freedom 
through it. So when he ended his address to the 
Electrical Engineers in 1889 he had still to tconfess 
that " the difficulties are so great in the way of 
forming anything like a great comprehensive theory, 
that we cannot even imagine a finger-post pointing 
a way that can lead towards the explanation." 

But now another turn was coming in the evolu 
tion of the theory, by the slowly-forming decision l 
that the vortex theory of atoms, at least in the form 
in which it had been enunciated, must be abandoned. 

1 In the late autumn of 1883 when Sir William Thomson lectured in 
Newcastle on atoms and vortex-rings, he and Lady Thomson were the guests 
of Dr. J. Theodore Merz, from whom he received a copy of the then newly- 
published Adams Prize Essay of Professor (now Sir Joseph J.) Thomson on 
Vortex Atom Rings. He travelled back to Glasgow with Dr. Harvey 
Goodwin, Bishop of Carlisle, with whom he keenly discussed the work. It 
was some three years later, when revisiting Newcastle to see the early form 
of Parsons s steam-turbine, that he told Dr. Merz that the vortex-atom theory 
* did not realize his expectations, inasmuch as it did not explain inertia or 


Lord Kelvin has himself told us of this conclusion 
in the following words : l 

It now seems to me certain that if any motion be 
given within a finite portion of an infinite incompressible 
liquid originally at rest, its fate is necessarily dissipation 
to infinite distances with infinitely small velocities every 
where ; while the total kinetic energy remains constant. 
After many years of failure to prove that the motion in the 
ordinary Helmholtz circular ring is stable, I came to the 
conclusion that it is essentially unstable, and that its fate 
must be to become dissipated as now described. I came to 
this conclusion by extensions not hitherto published of 
the considerations described in a short paper entitled : 
" On the Stability of Steady and Periodic Fluid Motion," 
in the Phil. Mag. for May 1887. 

He had, however, a gleam of light. Still brooding 
over his fateful paper of 1847, and the possible 
mechanical representations which he had then 
" reserved for a future paper," he began over again 
to consider an ideal ether which, though incom 
pressible, should have no distortional rigidity, but 
only an inherent quasi-elastic (gyrostatic) resistance 
to rotation. He found it to furnish a perfect sub 
stitute for the ordinary incompressible elastic solid 
as to equilibrium and motion throughout the 
interior, but having a vital difference in respect of 
the action at any interface between two portions 

1 Proc. Roy. Soc. Edin. vol. xxv. p. 565, footnote, June 20, 1904. The 
words now italicized in the quotation must be regarded as Lord Kelvin s 
renunciation of his hypothesis of the vortex-atom. Writing in 1898 to 
Professor Silas W. Holman, Lord Kelvin had said : "I am afraid that it is 
not possible to explain all the properties of matter by the vortex-atom theory 
alone, that is to say, merely by motion of an incompressible fluid ; and I have 
not found it helpful in respect to crystalline configurations, or electrical, 
chemical, or gravitational forces. . . . We may expect the time will come 
when we shall understand the nature of an atom. With great regret I abandon 
the idea that a mere configuration of motion suffices." 


having different rigidities of the kind considered. 
And now he was able, by aid of the idea of a 
circuital displacement of a portion forming in itself 
a closed curve, to represent magnetic force by the 
tangential drag on the surrounding medium. If 
such displacements were periodic in time, the kinetic 
result would be a propagation of magnetic waves. 
" We have thus simply the undulatory theory of 
light, as an inevitable consequence of believing that 
the displacement of elastic solid, by which in my 
old paper I gave merely a * representation of the 
electric currents and the corresponding magnetic 
forces, is a reality." But even so, the theory was 
incomplete. He had won a step forward by suppos 
ing all space filled with a plenum endowed with 
mechanical properties, it is true, but not with those 
of an ordinary elastic solid or an ordinary incom 
pressible fluid ; an ideal ether, satisfactory for optics 
at least, but unsatisfactory as a basis for an all- 
embracing theory. It did not represent electrostatic 
forces ; it did not explain why currents heat their 
conductors ; it did not prove that the velocity of 
light in ether is " v" How then did Thomson 
at this date, 1890, propose to escape from the 
intellectual impasse ? Let his own words tell : 

All this essentially involves the consideration of 
ponderable matter permeated by, or embedded in ether, 
and a tertium quid, which we may call electricity, a fluid 
go-between, serving to transmit force between ponderable 
matter and ether, and to cause by its flow the molecular 
motions of ponderable matter which we call heat I see 
no way of suggesting properties of matter, of electricity 


or of ether, by which all this, or any more than a very 
slight approach to it, can be done, and I think we must 
feel at present that the triple alliance, ether, electricity, 
and ponderable matter is rather a result of our want of 
knowledge and of capacity to imagine beyond the limited 
present horizon of physical science, than a reality of 
nature. Math, and Phys. Papers, vol. iii. p. 465. 

Note, in this remarkable pronouncement, the 
implication of the failure of the vortex-atom theory 
to explain apart from a something " which we may 
call electricity" the properties of matter. He 
knew none better than he that electricity whirling 
around generated magnetic force along the axis of 
its spin. If his supposed ether were not the same 
thing as free electricity, its whirls would not act 
magnetically ; and if it were not the same thing, how 
explain magnetism ? His suggestion now is : bring 
in electricity as " a fluid go-between, serving to 
transmit force " between matter and ether. 

" Looking back on this, however," observes Sir 
Joseph Larmor, 1 " one can see that the electron 
was not far off." Nevertheless the time was not 
come ; and so with this suggestive forecast the great 
comprehensive theory goes out of sight for ten years. 

But while the search for a dynamical mechanism 
which should explain light, elasticity, gravity, electri 
city, and magnetism was thus in abeyance, Thomson 
broke out into new activities. In connection with 
his suggestion of a foam-like structure for ether, in 
the winter of 1887-88, he had considered how space 

1 Obituary notice of Lord Kelvin, Prof. Roy. Soc. vol. Ixxxi. (Series A), 
p. 68. 

VOL. II 2 H 


might be so divided out into a system of adjacent 
cells that the total partitional area between cells of 
a given volume should be a minimum ; and, guided 
by experiments l on soap bubbles, he discovered, 
apparently to his surprise, that the form which 
fulfilled this condition was neither the cube, the 
octahedron, nor yet the rhombic dodekahedron, but 
the tetrakaidekahedron, with eight of its faces 
hexagons and six of them squares, resembling a 
cube with its six corners truncated, and with all the 
edges slightly curved. His " green books" for many 
months from this time are full of sketches and calcu 
lations respecting the geometrical and physical 
properties of assemblages of cells, or units, of this 
and other shapes. Deeper and deeper he dived 
into the matter, trying to assimilate all that was 
known of the systems of crystallography, of planes 
of cleavage, of twinning, of the integrating molecules 
of Haiiy, of the slipping-planes of Reusch, of the 
nets of points imagined by Bravais, in fact all that 
pertained to the physical properties of matter in the 
crystalline state. 

Then, in July 1889, he read to the Royal Society 
of Edinburgh a paper, 2 destined, surely, to become 
a classic in physics, entitled " The Molecular Con 
stitution of Matter." He began by a definition of 
crystalline structure, declaring that any homo 
geneous isotropic solid, such as glass, was but an 
isotropically macled crystal. Then he considered a 

1 See the narrative, p. 870, supra. 
2 Reprinted in Math, and Pkys. Papers, vol. iii. p. 395, 1890. 


homogeneous assemblage of points, each surrounded 
by a cell, all space being partitioned out into assem 
blages of cells, each cell a polyhedron of interfaces. 
Turning next to Father Boscovich s theory, that the 
ultimate atoms of matter are points endowed each 
with inertia, and with mutual repulsions or attrac 
tions, dependent only on mutual distances, he dis 
cussed the question of the equilibrium and stability 
of groups of two, three, four, or more atoms. This 
gave a basis for a Boscovichian kinetic theory of 
crystals, of liquids, and of gases. In a mere 
irregular random crowd of molecules it would be 
difficult to imagine equilibrium, either static or 
kinetic. Such a crowd might be a liquid but 
scarcely a solid. The molecular tactics of crystals 
depended on certain geometric principles of arrange 
ments which Bravais had laid down on the doctrine 
of homogeneous assemblages, in which planes of 
symmetrically distributed points were regarded as 
rtseaux or networks. Problems of closest packing 
in assemblages of globes, like piled shot, or of ellip 
soids, were readily treated geometrically. The artificial 
twinning of Iceland-spar, and the allied phenomena 
of changes of crystalline structure by pressure, 
could be accounted for by supposing slip to occur 
along planes of assemblage. Mathematical inves 
tigations of the conditions of equilibrium in such as 
semblages were reserved ; but models were described 
and shown, to realize elastic solids, both incompres 
sible and compressible, by bows of bent steel wire 
linked together by rings, and supported by tie-struts. 


At the British Association Meeting at Newcastle 
in September a further paper on the same subject 
was given by Sir William. Of this a contemporary 
account by Lodge appeared in The Electrician 
(vol. xxiii. p. 544). 

^ The other communication I have referred to, that on 
Boscovich s theory, might have been called the Mechanics 
of Crystallography, or Molecular Statics. It was a 
powerful and acute piece of pure mechanical reasoning, 
showing how a great number of the extraordinary 
behaviours of crystals, including some only recently 
discovered, and some which at first hearing seem quite 
incredible, can be accounted for by imagining the mole 
cules built up according to a certain law of force between 
the parts, a force attractive at some distances, repulsive at 
others, and not specially contemplating or troubling 
about how the forces arise, nor of what the substance of 
the molecules is composed treating them, in fact, as 
abstract centres of force (which they certainly are, how 
ever much else they also be) and ignoring their inertia, 
very much as Boscovich in his century-old memoir did. 
Crystals of various orders, hemihedral crystals, crystals 
with a periodic structure, and consequent curious selective 
reflexion for light, crystals that can be sheared, and 
molecules that are liable to fly to pieces and detonate, 
were all referred to, and models built up of spiral springs 
were used to illustrate them. 

Further considerations with a Boscovichian ex 
planation of the modulus of elasticity were given in 
February 1890 to the Royal Society of Edinburgh. 
Later, he wrote to Lord Rayleigh of matters in his 

mind : 


DEAR LORD RAYLEIGH. . . . Did you ever remark 
that if the density of ether changes as it moves across the 


interface between glass and vacuum, or between any two 
transparent bodies, in its actual vibrations of light, and 
if it is otherwise uninfluenced by ponderable matter, and 
if the rigidity is equal on the two sides of the interface, 
we have exactly Fresnel s laws of polarization by re 
fraction and reflection ? 

And if besides we have, for ether within the space of 
a ponderable body, a resistance to its motion relative to 
the ponderable matter, equal to the velocity multiplied by 
a coefficient which for different metallic bodies is pro 
portional to the density of the ether in them, and for 
transparent non-conductors is zero, we have Maxwell s 
equations of electromagnetic induction. This makes the 
electric conductivity of a metal proportional to the density 
of the ether in it ! Yours truly, 


Three years passed, and then came in May 1893 
the Royal Institution discourse on Isoperimetrical 
Problems ; illustrated by the problem of Queen 
Dido of Carthage, how to enclose the largest area 
of territory by an ox-hide cut into an exceedingly 
long strip, and by the problem of Horatius Codes, 
whose patriotism was rewarded with a grant of as 
much land as he could plough round in a day. In 
Lord Kelvin s hands these two problems of classical 
antiquity furnished the text for a discourse on 
Lagrange s Calculus of Variations, and Hamilton s 
principle of Least Action, leading to the geodetic 
exercise how to draw the shortest possible line 
between two given points on a curved surface. 
Pappus, who praised the honey-bee for its know 
ledge of the geometrical truth that a hexagon can 
enclose more honey than a square or a triangle with 
equal quantities of building material in the walls, 


had originated the term isoperimetrical, which now 
serves to denote that large province of mathematical 
and engineering science in which different figures 
having equal perimeters, or different paths between 
two given points, are compared in connection with 
definite questions of greatest efficiency or least cost, 
extending even to such questions as the proper 
laying-out of a railway line in a hilly country, or the 
dynamical relations between curvature and centri 
fugal force in the motion of a particle. 1 A few days 
later this was followed by the delivery, to the Oxford 
University Junior Scientific Club, of the Robert 
Boyle Lecture 2 for the year 1893, on tne Molecular 
Tactics of a Crystal. Under this title the geometry 
of crystalline structure was portrayed in great 
detail, with discussion of the boundaries of the par 
titioning cells 3 drawn around the integrating mole 
cules. The most general form of cell was not the 
parallelepiped but the tetrakaidekahedron. The 
closest packing of spheres or ellipsoids in a heap 
left but three degrees of freedom of strain, instead 
of the six presented by a natural solid ; and any 
distortion of the mass broke some of the contacts 
and brought about an expansion of it. This was in 
effect the dilatancy observed by Osborne Reynolds 
in sacks filled with corn, sand, or small shot. 

1 " I hope you found my lecture interesting," he said afterwards to Lord 
Alverstone, who was one of the audience. " I am sure we should, my dear 
Lord Kelvin," was the reply, " if we had understood it." 

2 Reprinted in Baltimore Lectures (1904), Appendix H, p. 602. 

3 He amplified this part of the subject in a Royal Society paper in 
January 1894, " On the Homogeneous Division of Space " ; wherein the reader 
will find discussions of the transformation of the parallelepiped into the 
tetrakaidekahedron, and of the relation of both to the tetrahedron. Inci 
dentally it contains also the theory of the designing of wall-paper patterns. 


Passing on to the subject of twinning, attention was 
drawn to the beautiful phenomena of internal 
coloured iridescent reflecting planes observed in 
some crystals of chlorate of potash, and due to a 
periodically-twinned structure. A reference to the 
" chirality " of quartz crystals according to which 
some of them are right-handed and others left- 
handed in their growth and a suggested explana 
tion of the same, completed the discourse. A 
mathematical discussion of the elasticity of a crystal, 
according to Boscovich, presented to the Royal 
Society in June and July 1893, carried the subject a 
little further ; and at the British Association meet 
ing in the following September a further extension 
to elucidate from geometry of structure the pyro- 
electric and piezo-electric properties of quartz and 
tourmaline was made. 

In 1893 was published a translation by Professor 
D. E. Jones of Hertz s collected researches 
Untersuchungen uber die Ausbreitung der Elektris- 
chen Kraft, to which, on the suggestion of Lord 
Kelvin, was prefixed the English title of Electric 
Waves. For this volume 1 Lord Kelvin himself 
wrote as Preface a striking appreciation. He asked 
the readers to carry their minds back to the time 
when Newton s doctrine of universal gravitation led 
to the general belief (not shared by Newton him 
self) that gravitation and other forces will act 

1 Electric Waves, being Researches on the Propagation of Electric Action 
with Finite Velocity through Space, by Dr. Heinrich Hertz. Authorised 
English translation by D. E. Jones, B.Sc., with a Preface by Lord Kelvin, 
LL.D., D.C.L., etc. London : Macmillan & Co., 1893. 


between bodies at a distance without the require 
ment of any intervening medium. Newton s well- 
known repudiation (in his letter of 1692 to Bentley) 
of this as an absurdity, was then contrasted with the 
" infinitely improbable theory " of Father Boscovich, 
in which all the properties of matter (except heat) 
were explained solely by action at a distance, by 
mutual repulsions and attractions between mathe 
matical points. Though Boscovich s theory had 
been unqualifiedly accepted as a reality before the 
end of the eighteenth century, a reaction set in in 
the middle of the nineteenth century, after Faraday s 
discovery of specific inductive capacity ; and before 
Faraday s death, in 1867, ^ e notion that electric force 
is propagated by a medium called ether was generally 
accepted by the rising generation of scientific men. 
Lord Kelvin then continued : 

Absolutely nothing has hitherto been done for gravity 
either by experiment or observation towards deciding 
between Newton and Bernoulli, as to the question of its 
propagation through a medium, and up to the present 
time we have no light, even so much as to point a way 
for investigation in that direction. But for electricity and 
magnetism Faraday s anticipations and Clerk Maxwell s 
splendidly-developed theory have been established on the 
sure basis of experiment by Hertz s work, of which his 
own most interesting account is now presented to the 
English reader. ... It was by sheer perseverance in 
philosophical experimenting that Hertz was led to dis 
cover a finite velocity of propagation of electromagnetic 
action, and then to pass on to electromagnetic waves in 
air and their reflexion. . . . 

Readers of the present volume will, I am sure, be 
pleased if I call their attention to two papers by Prof. 


G. F. FitzGerald, which I heard myself at the meeting of 
the British Association at Southport in 1883 One of 
them is entitled, " On a Method of producing Electro 
magnetic Disturbances of comparatively Short Wave 
lengths." The paper itself is not long, and I quote it 
here in full, as it appeared in the Report of the British 
Association, 1883: "This is by utilising the alternating 
currents produced when an accumulator is discharged 
through a small resistance. It is possible to produce 
waves of as little as two metres wave-length, or even 
less." This was a brilliant and useful suggestion. Hertz, 
not knowing of it, used the method ; and making as little 
as possible of the " accumulator," got waves of as little as 
twenty-four centimetres wave-length in many of his funda 
mental experiments. The title alone of the other paper, 
" On the Energy lost by Radiation from Alternating 
Currents," is in itself a valuable lesson in the electro 
magnetic theory of light, or the undulatory theory of 
magnetic disturbance. The reader of the present volume 
will be interested in comparing it with the title of 
Hertz s Eleventh Paper ; but I cannot refer to this paper 
without expressing the admiration and delight with 
which I see the words " rectilinear propagation," " polar 
ization," " reflection," " refraction," appearing in it as sub 

During the fifty-six years which have passed since 
Faraday first offended physical mathematicians with his 
curved lines of force, many workers and many thinkers 
have helped to build up the nineteenth century school of 
plenum, one ether for light, heat, electricity, magnetism ; 
and the German and English volumes containing Hertz s 
electrical papers, given to the world in the last decade 
of the century, will be a permanent monument of the 
splendid consummation now realised. 

Lord Kelvin s omission to refer to himself 
as having had any part in the building up of 
that nineteenth century school of thought is as 


noteworthy as his recognition of Maxwell s 
" splendidly-developed theory." 

In Lord Kelvin s Presidential Address of Nov 
ember 1893 to the Royal Society, he had much to 
say that bore upon the foundations of physics. In 
the first place, he announced as " not the least 
important of the scientific events of the year," the 
publication of Hertz s collection of papers on 
Electric Waves, and he repeated, almost verbatim, 
the appreciation which he had just written as the 
Preface to that work. Then, as if to check his own 
enthusiasm, he continued : 

But, splendid as this consummation is, we must not 
fold our hands and think or say there are no more worlds 
to conquer for electrical science. We do know something 
now of magnetic waves. We know that they exist in 
nature and that they are in perfect accord with Maxwell s 
beautiful theory. But this theory teaches us nothing of 
the actual motions of matter constituting a magnetic 
wave. Some definite motion of matter perpendicular to 
the lines of alternating magnetic force in the waves and 
to the direction of propagation of the action through 
space, there must be ; and it seems almost satisfactory as 
a hypothesis to suppose that it is chiefly a motion of ether 
with a comparatively small but not inconsiderable loading 
by fringes of ponderable molecules carried with it. This 
makes Maxwell s " electric displacement " simply a to-and- 
fro motion of ether across the line of propagation, that is 
to say, precisely the vibrations in the undulatory theory of 
light according to Fresnel. But we have as yet absolutely 
no guidance towards any understanding or imagining of 
the relation between this simple and definite alternating 
motion, or any other motion or displacement of the 

U |1M ether, and the earliest-known phenomena of electricity 

and magnetism the electrification of matter and the 

w o 


attractions and repulsions of electrified bodies ; the per 
manent magnetism of lodestone and steel, and the attrac 
tions and repulsions due to it : and certainly we are quite 
as far from the clue to explaining, by ether or otherwise, 
the enormously greater forces of attraction and repulsion 
now so well known after the modern discovery of electro- 

Having thus restated his sense of the need of a 
more comprehensive dynamical theory, he struck 
a new vein of thought : 

Fifty years ago it became strongly impressed on my 
mind that the difference of quality between vitreous and 
resinous electricity, conventionally called positive and 
negative, essentially ignored as it is in the mathematical 
theories of electricity and magnetism with which I was 
then much occupied (and in the whole science of magnetic 
waves as we have it now), must be studied if we are to 
learn anything of the nature of electricity and its place 
among the properties of matter. 

He then went on to enumerate the effects in 
which the vitreous and resinous electricity appear to 
be fundamentally distinct from one another : fric- 
tional electricity ; electro-chemistry ; pyro-electricity ; 
and piezo-electricity of crystals ; electric glow, brush 
and spark discharges ; also in the vast difference of 
behaviour of the positive and negative electrodes of 
the electric arc lamp. He referred to Faraday s 
investigations of discharge in vacuo, to his discovery 
of the "dark space" in the discharge, and to his 
remark : " The results connected with the different 
conditions of positive and negative discharge will 
have a far greater influence on the philosophy of 
electric science than we at present imagine." He 


reviewed the researches upon the electric dis 
charge in vacuo of a number of recent workers, in 
cluding Gassiot, Pliicker, Cromwell Varley, Crookes, 
Schuster, Joseph J. Thomson, and Fleming. 
Varley s discovery in 1871 of the molecular torrent 
from the negative pole, and Crookes s long con 
tinued train of brilliant discoveries came in for 
special mention. The radiometer ; the kathode- 
discharge in a high vacuum ; the molecular torrent 
projected from the negative pole, with its mechani 
cal, thermal, magnetic, and phosphorescent pro 
perties ; the electrical evaporation of negatively 
electrified liquids and solids ; the convergence of 
the kathode beam from the concave kathode of a 
focus-tube ; the mutual repulsion between two 
parallel kathode beams, all were enthusiastically 
referred to. He concluded thus : 

In the whole train of Crookes investigations on the 
radiometer, the viscosity of gases at high exhaustions, and 
the electric phenomena of high vacuums, ether seems to 
have nothing to do except the humble function of showing 
to our eyes something of what the atoms and molecules 
are doing. The same confession of ignorance must be 
made with reference to the subject dealt with in the 
important researches of Schuster and J. J. Thomson on 
the passage of electricity through gases. Even in 
Thomson s beautiful experiments showing currents pro 
duced by circuital electromagnetic induction in complete 
poleless circuits, the presence of molecules of residual gas 
or vapour seems to be the essential. It seems certainly 
true that without the molecules there could be no current, 
and that without the molecules electricity has no meaning. 
But in obedience to logic I must withdraw one expression 
I have used. We must not imagine that " presence of 


molecules is the essential." It is certainly an essential. 
Ether also is certainly an essential, and certainly has 
more to do than merely to telegraph to our eyes to tell 
us of what the molecules and atoms are about. If a first 
step towards understanding the relations between ether 
and ponderable matter is to be made, it seems to me that 
the most hopeful foundation for it is knowledge derived 
from experiment on electricity in high vacuum ; and if, 
as I believe is true, there is good reason for hoping to see 
this step made, we owe a debt of gratitude to the able and 
persevering workers of the last forty years who have given 
us the knowledge we have ; and we may hope for more and 
more from some of themselves and from others encouraged 
by the fruitfulness of their labours to persevere in the work. 

Two years more went by, and though others had 
been working on the recondite problems of the 
ultimate theory of matter and ether, Lord Kelvin 
had made no further utterance. At the close of the 
year 1895 came Rontgen s startling discovery of 
the new rays generated in a high vacuum by the 
impact of the kathode torrent upon some solid 
target ; rays that will penetrate even opaque solid 
bodies. Lord Kelvin s interest in this new revela 
tion was intense, and he discussed keenly with 
Stokes and others Rontgen s conjecture that these 
rays might consist of condensational waves in the 
ether. He himself favoured the suggestion, but 
saw tremendous difficulties in the way. Several 
letters written in the spring of the year 1896 show 
the zest with which he contemplated the bearing 
of the new discovery upon the ultimate problem 
of physics. They were addressed respectively to 
Professor Oliver Lodge (then in Liverpool), Sir 


George Stokes, Professor Leahy, and Professor 

February 4, 1896. 

DEAR LODGE I thank you for your letter of yester 
day and accompanying prints. I had read them in the 
Electrician and thought of calling your attention to 
" between Hittorf and Crookes." It is curious how 
generally it has been overlooked, how neatly and thor 
oughly Varley hit it off in respect to the molecular 
torrent from the Cathode, and left nothing to hit off 
about it except what has now been done by Perrin 
(whose paper I got Lockyer to put into last week s 
Nature} : not to speak of the brilliant and splendid 
and instructive demonstrations by Crookes of his own 
independent discovery of it. 

Do you remark how the nonsense about the " Cathode 
(undulatory) ray" and perverse rejection of Varley and 
Crookes (started I suppose by Hittorf and Goldstein but 
adopted by every one except Helmholtz, that I know of 
in Germany, including strange to say, Hertz and Lenard), 
has utterly lost to Lenard the discovery of the Rontgen 
New Light ? I am glad to see that you go for Hertz in 
this matter, but I think, in all probability he would have 
come right in it if he had lived and had fallen in with 
either Varley s or Crookes papers ; but I suppose his 
pupil Lenard, although very strong and persevering, has 
more of the German narrowness than Hertz. However I 
don t judge because of course we have already great 
things from Lenard (from Hertz s initiation) and may 
expect more and more from himself. I tried hard, but 
in vain, to get him to come to Ipswich and told him 
I wanted to fight him on the Kathodenj/nwz but that 
I was ready to call it ^/ if he could give 
convincing reason for his view. Yours truly, 


February 24, 1896. 

DEAR STOKES ... I have been trying almost in 
cessantly since some time before Nov. 28, 1846 (Art. 


XXVII. Vol. I. of my Mathematical and Physical Papers) 
for a mech&mcdil-dynamical representation of electrostatic 
force, but hitherto quite in vain. Many others, including 
Maxwell, have tried more or less for the same, but with no 
approach to a glimpse of what might become a success. 
It seems highly probable that there may be longitudinal 
waves in ether, but hitherto this idea does not help us 
to explain electrostatic force. 

As to the Rontgen light, what you say of high 
frequency seems to me of very great importance, but 
you need not confine it to "transversal vibrations." It 
is equally applicable to waves of longitudinal vibrations 
if there are any in ether. Excessively high frequency 
gives, according to the molecular theory which I learned 
from you before 1852, the same propagational velocity in 
all transparent mediums as in vacuum. 

March 6, 1896. 

DEAR PROF. LEAHY I am sorry to have been pre 
vented day after day from answering your letter of the 
27th. The explanation of my sentence which you quote 
is simply this : The attraction of rubbed amber or lode- 
stone is exhibited in virtue of their freedom to move, which 
they could not have if they were embedded in an elastic solid. 

Pulsating spheres, or other vibrating bodies on a fluid 
are free to mpve : and thus they show the attractions and 
repulsions due to vibration described by Faraday, Schell- 
bach and Guthrie and others ; and can be conceived as 
capable of showing the attractions and repulsions investi 
gated by various writers on theoretical hydrokinetics. 
Perforated solids with irrotational circulation of a liquid 
through the perforations are free to move, and ideally 
could show the forces described in 733 73 8 of my 
Electrostatics and Magnetism ; and a long pivoted body is 
free to show the directional tendency described in 
739) 74- None of those cases of fluid motion however 
help us in the slightest degree to a physical explanation 
of magnetic forces. 


You say in your letter of the 27th, " I am aware that 
at present a hydrodynamical theory holds the field." I 
cannot agree with this. No one has come within a 
million miles of explaining any one phenomenon of 
electrostatics or magnetism by hydrodynamical theory. 
No mechanical or physical theory of any kind holds the 
field, though we have really a wonderfully good know 
ledge of the matter of fact laws of electrostatics and 
magnetism through a vast variety of phenomena. 
Believe me, yours very truly, KELVIN. 

March 7, 1896. 

DEAR FITZGERALD . . . Meantime as to the 
Rontgen light, I am more and more disposed to think 
it is extreme ultra-violet light of transverse vibrations, 
and I believe Stokes, with whom I have had a good deal 
of correspondence within these last three weeks, is, I 
think, also much inclined to the same view. 

I was much interested in your last letter about electric 
action in the neighbourhood of a discharged air condenser. 
One thing at all events of my rude pencilling I see you 
have quite convinced yourself of : " the subject is almost 
infinitely difficult." And I think you and I may almost 
agree to delete the " almost." As to what takes place in 
the axis in each of my two diagrams, it is either longitudinal 
vibrations or what Stokes calls " push," which is equivalent 
to instantaneous transmission of pressure. A rigid globe 
suddenly set to vibrate to and fro in a straight line in an 
incompressible elastic solid is a mechanical illustration, 
but does not come within a million miles of being a 
dynamical representation or realisation of either electro 
static or electromagnetic action of any kind. . . .- Yours 
very truly, KELVIN. 

April 9, 1896. 

DEAR FITZGERALD I have been prevented each day 
since I received it from answering your letter of the 4th 
by unpostponable affairs, of which trying to find out 
something more about ether and electrostatic stress and 


magnetism has been one, and (a closely allied subject), 
a report on india-rubber tyres another. 

I certainly intend to add some annotations or appen 
dices to my Baltimore Lectures before republication. But 
there will be nothing to qualify or unsay in respect to 
page 9 (except perhaps lines 1 13-19). And I am begin 
ning now to be more hopeful in respect to the last com 
pleted paragraph of that page. I think the "ether" of Article 
XCIX of my collected Mathematical and Physical Papers, 
with perhaps a density (see Art. CIV of M.P.P.) greater 
than io~ 12 , and a virtual rigidity greater than 9 x io 8 , may 
really help, and may explain, not explain away, the ideas 
for ether suggested in B.L. page io. But whether my 
to-day s hopes or my despair of the day before yesterday 
may be to be fulfilled, the paragraph beginning at the foot 
of page 8 and the succeeding paragraph of page 9 are to 
be maintained uncompromisingly. It is mere nihilism, 
having no part or lot in Natural Philosophy, to be con 
tented with two formulas for energy, electromagnetic and 
electrostatic, and to be happy with a vector and delighted 
with a page of symmetrical formulas. " Giebt nur 
ein Wort (Mephistopheles) Rin wilrdiges Pergament \ 

I have not had a moment s peace or happiness in 
respect to electromagnetic theory since Nov. 28, 1846 
(see vol. i. p. 80 of M.P.P.}. All this time I have been 
liable to fits of ether dipsomania, kept away at intervals 
only by rigorous abstention from thought on the subject. 
I have been very nearly free from attacks for nearly a 
year, thanks to Maxwell-Boltzmann and Electrification of 
Air, till Rontgen s discovery brought on a fearful paroxysm 
which has lasted without intermission since the beginning 
of January. I have some hopes that this may be the last 
attack. This morning I have seen that detached portions 
of " ether " within steel could not but give it the magnetic 
reteritiveness which it has. Poisson s " coercive force " is 

1 To make what I meant clearer: in line 16, after "electric" insert 

"waves with," and in line 17 delete "as" (see heading, p. 45). And in 
line 17? for "simple vibrations" substitute "waves." 

VOL. II 2 I 


simply resistance against sliding between " ether " and 
ponderable matter. 

The greatest of my difficulties to get something to 
wards a physical theory out of the " mechanical repre 
sentation " (M.P.P. Art. XXVII) up to now has been the 
steel magnet. Next greatest perhaps has been electro 
static stress : next greatest perhaps magnetic induction of 
currents. The greatest of all was the mobility of magnets 
and electrified bodies, showing the ponderomotive forces 
experienced by them in virtue of the rigidity of the ether 
in which they are embedded. But this difficulty (?) is 
annulled by the ether of Article XCIX, which acts as an 
incompressible liquid except in so far as its virtual 
rigidity is called into play by frictionality between it and 
ponderable matter. The generation of heat by a current 
through a conductor only adds to electromagnetic theory 
all the difficulties of the kinetic theory of heat which 
seem to render nobody unhappy. But, alas ! even if we con 
sider this and all those other difficulties as now annulled, 
another arises which may be greater than all the rest 
put together : How is it that the molecules of air or 
other gas tearing through ether at velocities of 500 metres 
per sec. or thereabout stiffen it to resist electrostatic stress, 
and have much less of stiffening effect or perhaps a 
weakening instead of a stiffening effect when their average 
velocities are about a 1000 metres per second? (E. 
Becquerel, " On the Electrical Conductivity of Gases at 
high Temperatures," Phil. Mag. Dec. 1853.) Apropos 
of this, remark that no experiment hitherto published gives 
us the slightest evidence as to whether there is or is not 
a measurable current of electricity between two metals 
kept at a difference of potentials of I volt, 100 volts, 
1000 volts or 20,000 volts in the nearest approach to 
vacuum hitherto produced artificially. If I am wrong 
give me reference. Meantime Bottomley is arranging to 
answer by experiment in vacuums down to the I5th of a 
millionth of an atmosphere of gas not collapsible in the 
M Leod gauge. 

Returning now to your letter : With reference to 


page 45 of proof of B.L. : True displacement of the ether 
there must be according to the undulatory theory of light 
perpendicular to the direction of propagation and per 
pendicular to the axis of rotational motion and of dis 
tortion of the ether. We all agree that the axis of rotation 
and distortion is really and not merely nihilistically a line 
of magnetic force. The line of displacement in transverse 
waves is somehow closely connected with electrostatic 
force. Witness the production of a spark between the 
ends of a wire bent into a ring round a solenoid when 
the ends of the ring touch or nearly touch one another, 
and when a current through the solenoid is suddenly 
stopped. But there is also certainly a displacement of 
matter in the line joining the centres of the spheres 
in the case which I recently suggested in Nature, etc. for 

You will see on page 45, I am very cautious and 
merely speak of " probable " in respect to condensational 
waves in ether. There is certainly some displacement 
of matter in the direction of electrostatic force, but 
whether it is displacement of ether or displacement of 
electricity relatively to ether, or displacement of ether and 
electricity together, we cannot say. Certain it is that the 
energy of electrostatic force is not simply energy of a 
stressed homogeneous elastic solid. Your two queries 
which you " hope " I " will not answer." ( I ) Referring 
to spherical waves of transverse vibrations and to page 64 
of print of B.L. : Consider a shell between two concentric 
spherical surfaces very distant from the source, and take 
the portion of this shell a quadrilateral of nodal cones. 
Let the distance between two spherical surfaces be a 
small fraction of the wave-length, and let every diameter 
of the quadrilateral be very large in comparison with the 
wave length. The phase of the motion is the same 
throughout the quadrilateral shell. The diminution of 
the amplitude of the vibration from maximum in the 
middle of the shell to zero at every part of the boundary 
implies infinitesimal thickenings and thinnings in different 
parts of the shell to keep its volume constant. The case 


is precisely analogous to longitudinal waves or vibrations 
in a straight stretched wire. Nobody (not even Jaumann, 
I suppose,) would puzzle himself into speaking of trans 
verse vibrations in this case, when he thinks of the 
thickening of the wire in one part and the thinning in 
another, due to shortenings and stretchings ; provided the 
wave-length is very great in comparison with the diameter 
of the wire. But people have puzzled themselves with 
the case of wave-length moderate in comparison with 
the diameter, and have not quite seen what to make of it, 
though it is really obvious enough. The mathematical 
problem, involving columnar harmonics as I have called 
them, " Fourier-Bessel Functions " for wave-lengths neither 
very great nor very small in comparison with the diameter 
of a wire or rod of circular section, is really interesting. 
It gives a velocity of propagation intermediate between 
the Young s modulus velocity and the velocity of the con- 
densational-rarefactional wave. The extreme case of 
wave-lengths very small in comparison with the diameter 
is simply the well-known condensational -rarefactional 
wave in an infinite solid. 

Your query (2) referring to page 106 of print of B.L. 
The case of T very great puzzled myself about a 
month ago. It is not very easy to interpret the formula 
by itself for this case. But I saw easily enough by 
going back to the process which led to the formula 
that it gives for T = <x> simply the diminished velocity 
due to augmented density, as if the masses of all the 
shells were distributed equally through it without altering 
its rigidity. 

There is another interesting case included in the same 
work. Let the central nucleus be absolutely fixed : the 
velocity of propagation is infinitely great for T = co . 

Take T infinitely small and you find the wave 

velocity = ./ , the same as in pure ether. This explains 

the exceedingly small refractivities of aluminium and vul 
canite found by Rontgen, and of other substances found 
by other experimenters for the X-rays. But the explana- 


tion would be better if they were small negative instead 
of small positive, as found (not confidently) by Rontgen. 
Stokes and I have had a good deal of correspondence 
over all this, and about six weeks ago we both concluded 
that in all probability the Rontgen X-rays are of transverse 
vibrations of very short period. Yours very truly, 


Apri, 29, 1896. 

DEAR FITZGERALD Your letter of the i7th fol 
lowed me to London and I have been very busy ever 
since or I should have written sooner in reply. I am 
sure you will never find comfort in crystallization or 
anything analogous to it to explain waves of light in 
ether, or in anything else than the fundamental doctrine of 
the undulatory theory of light true transverse vibrations 
of moving matter subject to the law of inertia. Hence 
my " must " to which you object. 

Maxwell s expression, " electric displacement " is, I 
believe, absolutely true so far as it indicates a true dis 
placement of matter, as in the undulatory theory of light, 
but my difficulty is in respect to the electric quality 
concerned in this displacement. 

Electric force (X, Y, Z) cannot be a mere displace 
ment, because mere displacement does not in an elastic 
solid or in any conceivable " ether " give rise to energy 
equal to R 2 / STT per unit volume of field. I could not in 
Nov. 1846, nor have I, ever since that time, been able to 
regard " displacement " as anything better than a mere 
" mechanical representation of electric force." But I 
have always from that time till now felt, and I now still 
feel, that somehow or other we shall find rotation of a 
medium to be the reality of magnetic force. We may 
ideally make a dynamical model with an incompressible 
inviscid fluid to represent electricity percolating among 
interstices between ether and ponderable matter of a 
metallic conductor, and generating heat by the vibrations 
in ether which such percolation could not but produce, 
provided all the substances concerned are perfectly free 


from viscosity. It is not so easy to include in the model 
electrostatic force and charged condensers. Thus a dis 
placement of electricity relatively to ether, and the strain 
produced by the fluid trying to get through from vesicle 
to vesicle in the ether, but in an insulator not succeeding, 
would be the " electric displacement " and the electrostatic 

All this is very crude, but perhaps not absolutely 
unmanageable for an ideal mechanical model. In trans 
verse vibrations of light and magnetism the ether and the 
fluid in the vesicles would move together ; and the stress 
of the ether dragging molecules denser than itself in 
vesicles containing it so as to give it very nearly always 
the same motion as its own, would be an extreme case of 
electrostatic stress. 

But there can be no comfort whatever in any attempt 
at a physical theory of electricity and magnetism unless 
it provides us with a medium capable of giving the pro 
digiously great forces which we have in electromagnetism, 
and the smaller, but still very palpable forces of electro 
statics, and also at the same time permitting the free 
mobility of bodies through it, in virtue of which we feel 
those forces. When I wrote to you my letter of April 9 
I thought I saw how it was possible to find this last 
essential quality in my "ether" of M.P.P. Art. XCIX, but 
a day later I fell back into utter despair, in which I still 

You speak of " vectors and symmetrical equations " l 
for investigating " the rate at which an alternating 
electric current penetrates into a conductor," and " the 
equations which lead to an exactly similar propagation 
of electric currents into non-conductors." The former 

1 Symmetrical equations are good in their place, but " vector" is a useless 
survival, or offshoot, from quaternions, and has never been of the slightest 
use to any creature. Hertz wisely shunted it, but unwisely he adopted 
temporarily Heaviside s nihilism. He even tended to nihilism in dynamics, 
as I warned you soon after his death. He would have grown out of all 
I this, I believe, if he had lived. He certainly was the opposite pole of 
nature to a nihilist in his experimental work, and in his Doctorate Thesis 
on the impact of elastic bodies. 


are in reality vitally different from the latter ; and 
the latter are merely the equations of motion of an 
incompressible elastic solid. One of the chief things to 
be discontented with is the refractoriness of all attempts to 
bring the two classes of action into dynamical relation 
with one another, on any hitherto imagined constitution 
for ether, electricity, and matter. It is not the equations 
I object to. It is the being satisfied with them, and with 
the pseudo-symmetry (pseudo, I mean, in respect to the 
physical subject) between electrostatics and magnetism. 
I also object to the damagingly misleading way in which 
the word " flux " is often used, as if it were a physical 
reality for electric and magnetic force, instead of merely 
an analogue in an utterly different physical subject for 
which the same equations apply, see Electrostatics and 
Magnetism, 4, 5, and 6 (first published Feb. 1842). 
But enough of this carping about words ! If we could 
but get the slightest inkling of how a fragment of 
paper jumps to rubbed sealing-wax, or a fragment of iron 
to a lodestone, I could be supremely happy, and would 
be temporarily content not to ask more of ether, not 
even gravity. 

In your letter of the i/th you hit off exactly the right 
thing in respect to a sphere or two spheres in incom 
pressible jelly. But you omit to remark that the push 
along the axis giving a displacement inversely as the 
square or some higher power of the distance represents the 
alleged infinitely rapid propagation of longitudinal dis 
placement. What I have called the distant terms don t 
include longitudinal displacement in the axis. Think 
first of a rigid globe in an incompressible liquid. Start it 
instantaneously in motion in the direction of any diameter. 
Every particle of the liquid will take its proper motion 
instantaneously. Give now the liquid some rigidity ; the 
instantaneous motion all around will be the same as it 
was with no rigidity : but a distortional wave motion 
propagated at a finite velocity will follow. This is exactly 
the state of things represented by Maxwell s equations 
and worked out in an example by Hertz. 


Thanks for page 45, r 2 instead of .r 2 . The papyrograph 
was sometimes not clear, and my eye imperfect in detect 
ing errors in the print. 

Your spherule of water moving through ice which melts 
in front and freezes behind, is virtually the same in result 
as my despised shoemaker s wax. I stuck to my theory 
of a turbulent liquid as long as I thought I could get 
anything out of it, and no longer. 

I now abandon everything I have ever thought of or 
written in respect to constitution of ether . . . Yours 
ever truly. KELVIN. 

That the veteran of seventy-two should possess 
the mobility of thought revealed in these hitherto 
unpublished letters, is wonderful : but it is not more 
wonderful than the tenacity with which he held 
to that which seemed to him a real depositum of 
scientific truth. Though he had abandoned the 
vortex-atom theory, and was now ready to throw- 
away all preconceptions as to the constitution of the 
ether, he had never lost faith in dynamics or in the 
ether itself, or in the possibility of that ultimate 
solution which had been before him in 1846. 

Then came his Jubilee. 

Those who have followed the course of his per 
sistent endeavours to see below the surface of 
matter, as here narrated, will be able to appreciate 
the true inwardness of his confession : " One word 
characterizes the most strenuous of the efforts for the 
advancement of science that I have made perseveringly 
during fifty-Jive years ; that word is failure. I 
know no more of electric and magnetic force, or of 
the relation between ether, electricity, and ponderable 
matter than I knew and tried to teach to my students 


of natural philosophy fifty years ago in my first 
session as Professor" 

What was " the most strenuous " of his efforts 
for the advancement of science ? Assuredly not 
achievement of ocean telegraphy, nor the improve 
ment of the compass ; neither the limitation of 
geological time, nor the establishment of thermo- 
dynamic doctrine. Great and strenuous as were the 
efforts which each of these demanded, none of them 
can be compared with the fifty-years-long quest for 
the theory of matter. And here it is worthy of 
remark that the same integrity of judgment, the 
same refusal to find intellectual peace at the cost 
of intellectual sincerity, which in his earlier life had 
restrained him for three years from accepting Joule s 
ideas as to the mechanical equivalence of heat and 
work, had equally, and for thirty years, restrained 
him from finding satisfaction in Maxwell s theory of 
light. In the former case his suspense of judgment 
had been rewarded by the discovery not only of the 
Dissipation of Energy, but of the still more widely 
significant doctrine of Available Energy. The 
everlasting law of honour by which science was 
bound to face fearlessly every problem that can 
fairly be presented to it, bound him too. The great 
dynamical problem of matter was yet unsolved ; but 
it was not insoluble, at least not in his regard. 
There was not, there could not be, any permanent 
satisfaction for his mind while the great quest failed 
of its goal. Was the work hard ? Then the harder 
the more was it worth doing. Did the intricacies of 


it cause trouble ? Then let it be remembered that 
" tribulation, not undisturbed progress, gives life and 
soul, and leads to success, when success can be 
reached, in the struggle for natural knowledge." 
Not even then, at the age of seventy-two, could Lord 
Kelvin rest with the great problem still unsolved. 

Meantime other workers and disciples had 
brought new material to bear. Following out the 
ideas of Faraday and Maxwell as to electricity itself 
having a natural unit, justifying the expression l 
" one molecule of electricity," von Helmholtz had, 
in his Faraday lecture of 1881, carried the idea a 
stage further in emphasizing the signification of the 
laws of electrolysis. Following on the investiga 
tions of Thomson and Loschmidt as to the size of 
atoms, Johnstone Stoney, also in 1881, had estimated 
the amount of charge of electricity which is associated 
with one atom of hydrogen, or other monad element, 
as being about one one - hundred trillionth part 
(io~ 20 ) of a coulomb, and to this natural unit of 
electricity he, in 1891, gave the name of electron? 
which term is, however, now generally restricted to 
, the unit of resinous or negative electricity. 

Refined measurements by Sir Joseph J. Thomson 
and others showed that the kathode streams in 
Crookes s tubes were flights of free electrons, dis 
embodied from the atoms of matter with which they 
are usually associated. Sir Joseph had, in 1881, 
investigated the magnetic field due to a moving 

1 Maxwell, Electricity and Magnetism (1873), vol. i. p. 312. 

2 Lord Kelvin preferred to use the term elect rion. Sir Joseph J. Thomson 
prefers the name corpuscle. Both mean the same thing as electron. 


electric charge, and had remarked that the convec 
tion of this field involves an addition to its effective 
mass. More important still in the present connec 
tion, Sir Joseph Larmor, 1 in the years 1893 to 1897, 
developed a new dynamical theory of the electric 
and luminiferous medium. Adopting the same 
general line as Lord Kelvin, he proposed a gyro- 
static adynamic ether, which would have a rotational 
rigidity, but allow free movement of solid bodies 
through it, as the primordial medium. Then he 
definitely suggested that if the atom be regarded as 
containing electrons, the phenomenon of magnetism 
should be explained, not as a rotation of the ether 
itself, but as a rotation of the electrons. The 
electron itself was regarded as a strain centre 
in the homogeneous medium. Radiation is due 
solely to acceleration or retardation of the electrons, 
a point which Heaviside had previously elaborated. 
To this was added the speculation that the mass 
of each sub-atom is proportional to the number 
of electrons that it carries, and that each atom is 
constituted of an orbital system of electrons (as 
imagined by Sir Joseph J. Thomson), with inter 
atomic forces that are entirely or mainly electric^ 
A system of electrons ranged along a circle, and 
moving around it with such a speed as to give 
steadiness constitutes in fact a vortex-ring in the 
surrounding ether. Lord Kelvin had never postu 
lated the vortex-ring as including an electric charge 

1 Roy. Soc. Proc. liv., Dec. 7, 1893; PhM> Trans. A. 1894, p. 764; ib. 
A. 1895, pp. 695-743; ib. A. 1897, pp. 205-309; also his book, Aether 
and Matter, Cambridge, 1 900. 


as part of its constitution; but in 1890 he had 
arrived definitely at the view (see p. 1049) that a 
triple alliance with electricity as a constituent member 
was a necessity. Larmor s new theory made the 
ultimate element of matter not a vortex-ring, but 
an electric charge or nucleus of permanent ethereal 
strain. A whirling assemblage of such nuclei might 
act as a vortex-ring. Here was then a definite idea 
of a connection between matter and ether, a founda 
tion for a definite and universal theory. It is but fair 
to add that a very similar view had been indepen 
dently put forward at almost the same time by 
Professor H. A. Lorentz of Ley den. 

In the later part of this development we are to 
some extent anticipating, for before it was fully 
launched Lord Kelvin had himself resumed the 
quest. At the British Association Meeting of 
1896, at Liverpool, he read a paper on the mole 
cular dynamics of hydrogen, oxygen, ozone, and 
other gases, and of ice, water, and quartz crystal. 
The object of this communication was to find how 
much of the known properties of these typical 
substances can be explained without making any 
further assumptions than the conferring of inertia 
on a Boscovich atom. 

In 1897 he made several communications to the 
Royal Society of Edinburgh, amongst them one on 
some models illustrating the dynamical theory of 
hemihedral crystals. 

Again, in 1898, at the British Association Meet 
ing at Bristol, he spoke of the dynamical theory 


of refraction and dispersion ; of continuity in the 
undulatory theory between condensational waves, 
distortional waves, and electric waves. In 1899 he 
rediscussed magnetism and molecular rotation before 
the Royal Society of Edinburgh. He showed that 
an electrified body is set into rotation by the genera 
tion of a magnetic field around it. 

In the year 1900 Lord Kelvin brought before 
the Royal Society of Edinburgh, and again at the 
Congres de Physique in Paris, a new hypothesis of 
a startling kind, in a paper, 1 on the Motion Pro 
duced in an Infinite Elastic Solid by the Motion 
through the Space occupied by it of a Body acting 
on it only 2 by Attraction and Repulsion. The very 
title contradicts the old scholastic axiom that two 
different portions of matter cannot occupy the same 
space at the same time. He had been reconsider 
ing the old difficulty of the undulatory theory of 
light the motion of ponderable bodies through 
space occupied by an elastic solid, for so he still 
regarded the ether. To emphasize the point he 
appended this trenchant note : 

The so-called " electro-magnetic theory of light " does 
not cut away this foundation [elastic solid] from the old 
undulatory theory of light It adds to that primary 
theory an enormous province of transcendent interest and 
importance ; it demands of us not merely an explanation 
of all the phenomena of light and radiant heat by trans 
verse vibrations of an elastic solid called ether, but 
also the inclusion of electric currents, of the permanent 

1 Reprinted as Appendix A, p. 468, of the Baltimore Lectures. 

2 And so Father Boscovich, judged obsolete in 1884, and his theory, pro 
nounced " infinitely improbable "in 1893, was in 1900 " reinstated as guide." 


magnetism of steel and lodestone, of magnetic force, and 
of electric force, in a comprehensive ethereal dynamics. 

He conceived the atom as a spherical aggregation 
of ether of varying density, of the same average 
value as the density of the ether outside, the 
internal ether being arranged in concentric shells of 
varying density, according to some prescribed law of 
force. It would have no resultant attraction on the 
ether outside, and could move freely through it at 
any speed that was small compared with the velocity 
of light. To reconcile the hypothesis with the 
experiment in which Michelson and Morley found 
the ether in the earth s atmosphere to be at rest 
relatively to the earth, he was prepared to accept 
the suggestion of FitzGerald and Lorentz that the 
motion of ether through matter may slightly alter 
its linear dimensions. There was nothing electrical 
in this hypothesis. 

The year 1901 brought a marked step forward. 
Under the quaint title of "Aepinus Atomized," 
Lord Kelvin sought to reconstruct the old one- 
fluid theory of electricity on a new atomic 
k hypothesis. The doctrine of Aepinus 1 was that 
positive and negative electrifications consist in 
excess above, and deficiency below, a natural 
quantum of a fluid called the electric fluid per 
meating among the atoms of ordinary matter. 
Adopting the modern notion of electrions (see 
p. 1074 supra), Lord Kelvin now suggested that 

1 Aepinus, Tentamen Theoria Electricitatis et Magnetismi, St. Peters 
burg, 1759. 


while electrions permeate freely through all space, 
whether occupied by ether or occupied also by the 
volumes of finite spheres constituting the atoms of 
ponderable matter, each electrion in the interior of 
an atom of matter experiences electric force towards 
the centre of the atom, just as if the atom contained 
within it, fixed relatively to itself, a uniform dis 
tribution of ideal electric matter. The electrions 
themselves were to be exceedingly minute atoms of 
resinous electricity, while the atom of matter was 
vitreously electrified. An atom might require one, 
two, or more electrions to neutralize it. The 
mathematical laws of the mutual actions of two such 
atomic structures were deduced, and an explanation 
found for the attractions and repulsions the oldest 
known electrical property produced by friction. He 
then calculated the conditions of stable equilibrium 
for a number of possible configurations of electrions 
within the atom ; two, on a diameter ; three, at the 
corners of a triangle ; four, at the corners of a 
square ; four, at the corners of a tetrahedron ; six, at 
those of an octahedron; eight, at those of a cube; and 
so on up to as many as twenty-one electrions. He 
found that hypothetical atoms so constituted would 
realize Faraday s explanation of the phenomenon 
of dielectric polarization. High temperature would 
set the electrions into wildly irregular vibrations, 
causing some of them to be occasionally shot out 
of their atoms, and either falling back or passing 
into other atoms, thus explaining the conductivity 
of solids such as glass or Nernst filaments, when 


heated. Considerations of the pyro-electric pro 
perties of crystals concluded the paper. 

The molecular dynamics of crystals was resumed 
in 1902 in a further paper 1 to the Royal Society of 
Edinburgh, with elaborate calculations on Bos- 
covichian principles of the stability or otherwise of 
networks of homogeneous assemblages of atoms. 

The completion of the Baltimore Lectures was 
now taken in hand. Chapter XIX was rewritten, 
with a reconciliation between the formulae of Green 
and Fresnel on the basis of the new hypothesis of 
1900, by which the character of the action of atoms 
of matter on ether was reduced to simple attraction 
or repulsion ; and these attractions were rendered 
effectual by assuming that the ether within the 
space occupied by the atom could be condensed or 
rarefied by positive or negative pressures due to 
repulsion or attraction exerted upon it by the atom 
and its neutralizing quantum of electrions. This 
assumption of compressibility removed the last 
difficulty in reconciling with dynamical theory, 
provided one might regard the inertia of crystals 
to be no longer isotropic, an idea which he had 
formerly rejected as incompatible with the con 
servation of energy. Lecture XX as thus rewritten, 
dealt with the chirality of quartz and of optically 
active liquids, on the new assumption of aeolotropic 
inertia. He desired to extend the explanation to 
the magneto-optic rotation, but contented himself 
by saying : " When we have a true physical theory 

1 Reprinted as Appendix J, p. 662, of the Baltimore Lectures. 


of the disturbance produced by a magnet in pure 
ether, and in ether in the space occupied by pon 
derable matter, fluid or solid, there will probably be 
no difficulty in giving as thoroughly satisfactory 
explanation of the magneto-optic rotation as we 
now have of the chiro-optic." He then returned 
to the dynamics of ordinary and anomalous dis 
persion, for which in 1884 he had invented his 
spring- shell model molecules, to consider what 
modification must be made to suit the hypothesis 
of the electrionic structure of the atom. In the new 
theory each electrion or each group of electrions 
within the atom could act as a vibrator, 1 which in a 
source of light takes energy by collision with other 
atoms and radiates out the energy in waves in the 
ether. He had been looking all along for a system 
of vibrators whose motions would explain the 
dynamics of spectrum analysis, the absorption of 
the dark lines of the spectrum, and the anomalies of 
dispersion. He had found them in the electrions. 
Assuming the electrion to be massless, or rather as 
possessing virtual inertia only on account of the 
kinetic energy of its motion through the ether, he 
solved the equations of motion and deduced that 
the greater the wave-length of the outgoing waves, 
the smaller was the proportionate loss of energy per 
period. This led finally to a new design of model 

1 It is a singular fact that in none of this later work does Lord Kelvin 
refer to the effect discovered in 1897 byZeeman, being conclusive as to the 
electrions being the real vibrators, not the atoms themselves or the molecules. 
His sole reference to the Zeeman phenomenon is in his 1899 paper on 
Magnetism and Molecular Rotation (p. 1077, supra), where he simply accepts 
Lorentz s theory. 

VOL. II 2 K 


molecule. In the old model there was as vibrator a 
central free mass connected by springs to a rigid 
sheath, the lining of a spherical cavity in ether. In 
the new electro-ethereal design, the force of the 
springs was replaced by the electric attraction of the 
atom on its electrion when the latter was displaced 
from its position of equilibrium ; and the electrion 
acts directly on the ether in simple proportion to 
acceleration of relative motion. He had found, 
then, the tertium quid pronounced in 1890 (see 
p. 1048) to be wanting. Every one of the formulas 
was found to be applicable, " notwithstanding the 
vast difference between the artificial and unreal 
details of the mechanism thought of and illustrated 
by models in 1884, and the probably real details 
of ether, electricity, and ponderable matter suggested 
in 1900-1903." 

How far, then, had his aspirations been fulfilled ? 
Let his own words say, as he wrote them in January 
1904 in the Preface to the Baltimore Lectures. 

It is in some measure satisfactory to me, and I hope it 
will be satisfactory to all my Baltimore coefficients still 
alive in our world of science, when this volume reaches 
their hands ; to find in it dynamical explanations of every 
one of the difficulties with which we were concerned from 
the first to the last of our lectures of 1884. . . . 

It seems to me that the next real advances to be 
looked for in the dynamics of ether are : (i) An explana 
tion of its condition in the neighbourhood of a steel 
magnet, etc. (ii) An investigation of the mutual force 
between two moving electrions, modified from a purely 
Boscovichian repulsion ; as it must be by the composi 
tion, with that force of a force due to the inertia of the 


ether set in motion by the motion of each of the electrions. 
It seems to me that, of these, (ii) may be at present 
fairly within our reach ; but that (i) needs a property of 
ether not included in the mere elastic-solid-theory worked 
out in the present volume. My object in undertaking the 
Baltimore Lectures was to find out how much of the 
phenomena of light can be explained without going 
beyond the elastic -solid -theory. We have now our 
answer: everything non-magnetic ; nothing magnetic. The 
so-called " electromagnetic theory of light " has not helped 
us hitherto : but the grand object is fully before us of 
finding a comprehensive dynamics of ether, electricity, and 
ponderable matter, which shall include electrostatic force, 
magnetostatic force, electromagnetism, electrochemistry, 
and the wave theory of light. 

Thus after twenty years the Lectures were 
completed. 1 With the discovery of radium and the 
persistent disintegration of its atoms by the emission 
of electrons and of vitreously electrified atoms of 
helium (as now known), the old problems had 
assumed a new aspect. Lord Kelvin sought to 
explain 2 these phenomena also by aid of his electro- 
etherial hypothesis. 

1 " The thanks of the scientific world," wrote Larmor, when reviewing 
the volume in Nature, " will surely go out to the veteran author, now by a 
happy choice Chancellor of the University which he has so long adorned, for 
this splendid gift, which stimulates and educates even where it fails to con 
vince, and bears on every page evidence of profound and unwearying thought." 

2 Of these latest contributions to science the titles are : " Plan of a 
Combination of Atoms having the Properties of Polonium or Radium " 
(Phil. Mag. viii. p. 528, Oct. 1904); " Models of Radium Atoms to give 
out a- and j8-Rays respectively" (Nature, Ixx. p. 514, Sept. 22, 1904); 
"On the Kinetic and Statistical Equilibrium of Ether in Ponderable Matter 
at any Temperature" (Phil. Mag. x. p. 285, Sept. 1905); "Plan of an 
Atom to be capable of storing an Electrion with enormous Energy for Radio 
activity" (Phil Mag. x. p. 695, Dec. 1905) ; "The recent Radium Con 
troversy" (Nature, Ixxiv. p. 539, Sept. 27, 1906); "An Attempt to 
Explain the Radio-activity of Radium" (Phil. Mag. xiii. p. 313, March 
1907); "On the Motions of Ether produced by Collisions of Atoms or 
Molecules containing or not containing Electrions" (Phil. Mag. xiv. p. 317, 
Sept. 1907) ; " On the Formation of Concrete Matter from Atomic Origins" 
[posthumously published] (Phil. Mag. xv. p. 397, April 1908). 


To sum up that which Lord Kelvin effected in 
this life-long labour were no easy task. To bring 
all the properties of matter within the range of 
dynamics involves an implication not readily con 
ceded. Dynamics is the science of matter and 
motion, or rather of matter and energy, since energy, 
not motion, is subject to a law of conservation. Is 
it then possible to reduce all physical phenomena 
within the duality of matter and energy ? Grant 
merely the duality, and we may explain not only the 
mechanics of moving bodies, but also sound and 
heat (except radiation), and, under certain assump 
tions, elasticity; but not gravitation, nor light. 
Light demands an ether, as well as energy and 
matter : it can no-how be explained by postulating 
a duality, unless matter itself is expressible in terms 
of ether and energy. And to explain electric 
phenomena (to say nothing of magnetic) demands 
four fundamental entities, electrons (or at least 
something called electricity), matter, energy, and 
ether. The trend of modern ultra-physics with 
respect to the constitution of matter is towards the 
following five categories : ( i ) the ether, that is, the 
plenum filling space ; (2) the electron, conceived as 
a plexus in the ether, probably of two species ; (3) 
the atom, a complex of electrons in the ether ; (4) 
the molecule, a specific group of atoms (or in some 
cases one atom) ; (5) the mass, an assemblage of 
molecules. Energy is involved in the construction 
of any of these out of any other. Now our 
mechanical ideas and language are all derived from 


masses and their movement ; and our chemical 
ideas and language mostly from molecules and their 
constituent atoms. There arises consequently a 
difficulty, inherent in the terms we use, and the 
physical implications due to their origin in our 
experience, when we try to explain or even to 
describe electrons and ether ; for to state the de 
scriptions intelligibly we must frame them in terms 
of ordinary matter, masses, or molecules. It would 
seem logical to restate the more complex in terms 
of the more simple, rather than the reverse, were 
the simple familiar to us. Lord Kelvin s effort 
seems to have been to find a theory to reduce 
the necessary concepts to the smallest number 
matter and energy, or, by means of the vortex 
theory, to ether and energy. In the end he found 
it necessary to bring in electricity as well. But who 
shall call this failure ? The late Professor Fitz- 
Gerald voiced the verdict of his fellow-workers in 
phrases of no uncertain import : 

Though he himself has described these efforts as 
resulting in failure, his contemporaries and disciples see a 
succession of brilliant successes, which have not, indeed, 
fully conquered the citadel of ignorance against which 
they were directed, but have, nevertheless, conquered 
many and fair districts, and advanced the armies of know 
ledge in their reconnaissance of this citadel to an extent 
that was only possible for a great general, an indefatigable 
and enthusiastic genius. 



FROM many passages in the previous chapters 
some insight is afforded into the views and opinions 
of Lord Kelvin upon religion, politics, education, 
and other questions. It were an unseemly thing, 
and altogether beyond the province of the present 
work, or the competence of its compiler, to essay to 
sit in the seat of judgment. Not in our generation 
will it be possible to exercise dispassionate vision 
or to disentangle the ultimate from the obvious. 
Whenever possible, the attempt has been made to 
cite Lord Kelvin s own words. But the presentation 
of his character afforded by these scattered utter 
ances would be very incomplete were not some 
effort made to gather together the stray threads. We 
shall not look upon his like again ; and the things 
in him which some took for defects must one day 
be evaluated afresh in the light of that essential 
nobility of character which shines out the brighter, 
the closer one comes to his own words and work. 

Though in the matter of religious beliefs Lord 
Kelvin never made any parade of his views, he was 

a man of earnest convictions, quietly but tenaciously 



sustained, without bigotry or intolerance. Although 
brought up in the Established (Presbyterian) 
Church of Scotland by his father, who had himself 
at one time studied for the ministry, he conformed 
while at Cambridge to the Church of England, and 
subscribed the Thirty-nine Articles both on his 
entry as an undergraduate and on his admission to 
the Fellowship in 1845. ^ is equally clear that in 
1846, on his election to the Glasgow Chair, he 
subscribed to the Westminster Confession. Also, 
during the lifetime of his first wife, and during his 
widowerhood, whenever he was at Largs he attended 
there the services of the Free Church, of which his 
wife s brother-in-law, the Rev. Charles Watson, was 
minister. When in Glasgow he regularly attended 
the services (Established, Presbyterian) of the 
University Chapel. Later in life he had sittings in 
the Scottish Episcopal Church in Glasgow, and also 
attended the Episcopal Church at Largs. He was, 
in fact, a regular and reverent communicant in the 
Church 1 of England. His brother James, when 
quite a young man, had, after great mental struggles, 
broken from the old Calvinistic faith, and definitely 
became a Unitarian. A letter of Dr. King s, of 
date 1850, shows that William reasoned very 

1 Of sacerdotalism and ritualism in all its phases and forms he had an 
unconcealed detestation. He even went once so far as to write that the only 
sense in which he could regard the " High " Church as high, was the 
same as that in which game is said to be " high" when it is decomposing. 

At a meeting of the Ladies Protestant League, held on July 16, 1902, 
Lord Kelvin said : "All well-wishers of England, and of religion in 
England, must lament that there has been so much of perversion allowed to 
pass unchecked within the Church of England, with only too feeble 
remonstrance on the part of the Bishops, to whom they had the right to look 
for the maintenance of law and order in the Church." 


strongly with his brother in favour of the evidence 
for revelation. Though James remained a staunch, 
if not at any time an extreme, adherent of the 
Unitarian faith, William never permitted this frank 
divergence of beliefs to lessen his affection or his 
freedom of intercourse and it was an intercourse 
of unusual warmth with his brother. One who 
from his boyhood knew Lord Kelvin well says of 
him : I am quite sure that he was sincerely 
religious : I would say he was a sincere Christian 
(meaning by Christianity the religion taught by Christ 
rather than the religion taught by the churches). 
I believe he looked deep into essentials, and that he 
regarded differences of sects as mere matters of 
form, and looked on the distinctions between 
Episcopalians, Presbyterians, Quakers, and Uni 
tarians with supreme indifference." To his nephew 
and nieces who held Unitarian beliefs he never 
expressed any disapproval ; neither did they feel 
that there existed any religious barrier between 
them and him ; nor did he scruple to suggest that 
an unbaptized person of sincere convictions should 
take the communion in church. 

In 1895, as President of the Royal Society, it 
fell to him, in his annual address, to speak of the 
death of Professor Huxley, to whose views he then 
referred in the following terms : 

Even those purely scientific papers contain ample 
evidence that Huxley s mind did not rest with the mere 
recording of results discovered by observation and experi 
ment : in them, and in the nine volumes of collected 
essays which he has left us, we find everywhere traces of 


acute and profound philosophic thought. When he 
introduced the word agnostic to describe his own feeling 
with reference to the origin and continuance of life, he 
confessed himself to be in the presence of mysteries on 
which science had not been strong enough to enlighten 
us ; and he chose the word wisely and well. It is a 
word which, even though negative in character, may be 
helpful to all philosophers and theologians. If religion 
means strenuousness in doing right and trying to do 
right, who has earned the title of a religious man better 
than Huxley ? 

Following the old custom in Glasgow College, 
he always, as narrated on p. 444, began his morning 
lecture by reciting, with quiet solemnity, the Third 
Collect, for Grace, from the close of the Service of 
the Church of England at morning prayer. As a 
young man he had thought things out in his own 
way, and had come to a faith which, not having 
been received second-hand, but being of personal 
conviction, was never afterwards shaken. His faith 
was always of a very simple and child-like nature, 
undogmatic, and unblighted by sectarian bitterness. 
It pained him to hear crudely atheistic views ex 
pressed by young men who had never known the 
deeper side of existence. 

Though Lord Kelvin did not like to miss attend 
ance at church on Sunday mornings, he was by no 
means a rigid Sabbatarian, and had no objection 
to lighter occupations, or to occupying himself with 
scientific calculations on Sundays. When sailing in 
his yacht he liked to put in on Saturday at some 
port, that his captain and crew might have Sunday 


In 1879 he declined to become a Vice-President 
of the Sunday Society, explaining that if its object 
had been simply to obtain the opening of museums, 
galleries, libraries, and gardens on Sundays, he 
would have been happy to join it ; and in 1872 he 
declined the Vice- Presidency of the Sunday Lecture 
Society, though he wished well to its efforts. In 
1889 he presided at the annual meeting of the 
Christian Evidence Society ; and from 1903 to his 
death was President of the Largs and Fairlie 
Auxiliary of the National Bible Society of Scotland. 

In 1888, when staying for a week with his sister 
Mrs. King in St. John s Wood, he himself, during 
a wet Sunday, suggested a Bible reading, which his 
nieces remember well, and of which they made notes 
at the time. He thought that in all Bibles the 
dates at the tops of the pages should be printed 
with a query-mark, except in the cases of ascertained 
historical events. The same evening Mrs. King 
read from Darwin s works the passage in which he 
expresses his disbelief in Divine revelation, and in 
any evidence of Design. Sir William pronounced 
such views utterly unscientific, and vehemently 
maintained that our power of discussing and specu 
lating about atheism and materialism was enough to 
disprove them. Evolution, he declared, would not 
in the least degree explain the great mystery of 
Nature and Creation. If all things originated in 
a single germ, then that germ contained in it all 
the marvels of creation physical, intellectual, and 
spiritual to be afterwards developed. It was 


impossible that atoms of dead matter should come 
together so as to make life. 

He was strongly opposed to the " secular solu 
tion " of the religious difficulty in primary education. 
He was equally strongly opposed to denomina- 
tionalism in schools, particularly for Ireland. 

Again and again, in his public career, from his 
inaugural lecture of 1846 to the end his life, Lord 
Kelvin declared his belief in Creative Power, and in 
an overruling Providence. In two points at least 
his scientific studies brought him to what he con 
sidered a direct demonstration of a definite creation : 
namely, the Fourier equations for the flow of heat, 
with the mathematical inference, pointed out on 
p. in, that there must have been a beginning ; and 
the vortex-atom conception (p. 517), according to 
which the permanence of the atom proves that no 
known animate or inanimate physical agency could 
have originated them. Yet he was never prone to 
drag in a teleological view as an excuse for shirking 
a deep-reaching investigation. " If," he said in 
1871, in discussing the origin of life on the earth, 
"a probable solution, consistent with the ordinary 
course of nature, can be found, we must not invoke 
an abnormal act of Creative Power." With Paley s 
Natural Theology he had been familiar from his 
youth ; and though he deplored the frivolities of 
teleology, he considered as solid and irrefragable the 
main argument of "that excellent old book." He 
seems in some way to have linked the argument for 
creative design with his belief in a comprehensive 


theory of ultimate dynamics. This appears in the 
closing sentence of his Royal Institution discourse 1 
of 1860 (see p. 408), where he had been putting the 
question whether we are to fall back on facts and 
phenomena, and renounce all idea of penetrating 
that mystery which hangs round the ultimate nature 
of matter. His comment was : " But it does seem 
that the marvellous train of discovery, unparalleled in 
the history of experimental science, which the last 
years of the world have seen to emanate from 
experiment within these walls, must lead to a stage 
of knowledge in which laws of inorganic nature will 
be understood in this sense that one will be known 
as essentially connected with all, and in which unity 
of plan, through an inexhaustibly varied execution, 
will be recognized as a universally manifested result 
of creative wisdom." 

The limitation of the above statement to inor 
ganic nature is characteristic ; it finds its parallel in 
many other instances, as, for example, in the limitation 
introduced by him into his statement (p. 282) of the 
thermodynamic axiom as to the impossibility of 
deriving mechanical energy by means of inanimate 
material agency, by cooling a body below the 
temperature of its surroundings. He regarded life, 
however certainly its operations were governed by 
chemical and dynamical laws, as essentially outside 
the range of physics. He utterly repudiated all idea 
of the generation of living matter by force or motion 
of dead matter alone. " That life proceeds from life, 

1 Proc. Roy. Institution^ vol. iii. pp. 277-290. 



and from nothing but life," was for him "true 
through all space and through all time" (p. 605). 
He declared 1 that whereas the fortuitous concourse 
of atoms was the sole philosophic foundation for the 
second law of thermodynamics, the fortuitous con 
course of atoms was powerless to account for the 
directed operations of living matter. " The influence 
of animal or vegetable life on matter is," he declared, 
" infinitely beyond the range of any scientific inquiry 
hitherto entered on. Its power of directing the 
motions of moving particles, in the demonstrated daily 
miracle of our human free-will, and in the growth of 
generation after generation of plants from a single 
seed, are infinitely different from any possible result 
of the fortuitous concourse of atoms." 

He had, in 1852 (p. 290), denied the probability 
that organized matter, either vegetable or animal, 
could reverse the thermodynamic dissipation of 
energy (a question which Helmholtz left open), and 
held this view unchanged in 1892. And again, in 
1874, he had said: " If the materialistic hypothesis 
of life were true, living creatures could grow back 
wards with conscious knowledge of the future but 
no memory of the past, and would again become 
unborn. But the real phenomena of life infinitely 
transcend human science ; and speculation regarding 
consequences of their ultimate reversal is utterly 

" The only contribution of dynamics to theoretical 
biology is," he declared (Popular Lectures, vol. i. 

1 Fortnightly Review, March 1892 ; and Popular Lectures, vol. ii. p. 464. 


p. 415), "absolute negation of automatic commence 
ment or automatic maintenance." 

But if he held that life was thus a thing apart 
from the physical forces which it controlled (and 
requiring in itself initially a creative act), his doctrine 
had little in common with the old crude vitalism 
which postulated a vital force as amongst the natural 
forces, so-called, which operate on matter. On the 
contrary, he maintained with the utmost strictness 
the rigorous insistence on physical forces to produce 
physical effects ; and his life-long struggle to reduce 
to terms of dynamics the other manifestations of 
energy rules out any such confusion. The human 
body, as a machine, was subject to the laws of 
mechanics ; as a digestive apparatus, to the laws of 
chemistry. No supposed vital force could maintain 
the animal heat : it was maintained by the con 
sumption of food and the processes of respiration 
through metabolism. True, the body did not work 
as a thermodynamic engine, it more nearly resembled 
an electric motor ; but the doctrine of available 
energy might be extended hereafter to embrace 
the physiological workings of energy. But all this 
required only that some vital principle should direct 
or organize those transformations of energy which 
would otherwise be conducted as a purely inorganic, 
that is, unorganized process ; no vital principle could 
physically supply the energy needed in the process 
which it merely directed. But the real phenomena 
of life were infinitely beyond the range of all sound 
speculation in dynamics. So far as physics was 


concerned, free-will was a miracle. Emphatically, 
Science was not, for him, eine entgotterte Natiir. 

In 1897, at ^e request of Sir George Stokes, 
Lord Kelvin gave the Annual Address to the 
Victoria Institute, a Society whose object is the 
reconciliation of religion and science. The subject 
was the Age of the Earth ; the scientific points of 
it are noted elsewhere. It ended with the state 
ment that mathematics and dynamics fail us when 
we are confronted with the problem of the origin of 
life on the earth. " We must pause, face to face 
with the mystery and miracle of the creation of 
living creatures." 

In the autumn of 1903, Sir Edward Fry, staying 
at Largs, wrote to a member of his family some 
personal impressions of visits to Netherhall, and 
he now kindly permits the publication of the follow 
ing extracts : 

As we have seen a good deal of Lord and Lady Kelvin whilst 
at Largs, and as Lord Kelvin is a most remarkable man, and as 
I know you will like to hear about him, I will put down my 
recollections whilst they are fresh in my mind. 

Lord Kelvin s house, Netherhall, is not a very large place 
rather a seaside villa with grounds than a seat and near him 
lives Dr. Watson, the Free Church minister of Largs, who married 
a sister of Lord Kelvin s first wife and these two old people 
seem on terms of great intimacy with Lord Kelvin. He was till a 
few years ago a member of Dr. Watson s congregation, but the 
differences about Home Rule, I believe, led to Lord Kelvin 
frequenting the Episcopalian service; and one afternoon Canon 
Low came to consult Lord Kelvin as to the vacancy in the 
bishopric to which the Largs Episcopalians owe allegiance. 

Lady Kelvin evidently devotes herself to the tender care of 
the precious piece of humanity in her keeping, and likes to talk 
about him. She showed us one of the series of books in which 
Lord Kelvin works. It is a quarto sized note-book which he 
always carries with him in a pocket made for the purpose, and in 


which he works away at his mathematical investigations when 
travelling by railway or at any time but hardly ever alone, as 
conversation does not disturb him. Each entry begins with an 
exact date, day and hour, and seemed the most extraordinary 
web of mathematical formulae, sometimes preceded by a state 
ment of the question to be solved. He is now at work on the 
development of a set of lectures given by him ten years ago in 
Baltimore when he went to America under urgent pressure, and 
gave 21 lectures, generally of ij hours length, in 17 days, and got 
back in time for his Glasgow course. From that time till a little 
while ago he had not found time to develop the lectures he then 
delivered ; but when he resigned his professorship Lady Kelvin 
says that he felt no lack in his life, but went steadily on with his 
work as if no change had occurred. 

She told me that Lord Kelvin had been invited to deliver the 
Giffard lectures, and that he had considered the subject, but felt 
that whilst he could have given one lecture on the subject, he 
could not undertake to give two courses. He went back to 
Paley s Natural Theology, and studied it, and said that he could 
add nothing to what Paley had said, which rather surprised me, 
seeing how little Paley s argument is often thought of nowadays. 

He is, she told me further, always willing to go anywhere for a 
definite purpose, and has a pleasure in scenery, but never really 
wishes to be away from home. 

Lord Kelvin is much interested in the current questions of the 
day, strongly opposed to the behaviour of the motorists, and 
inclined to be very angry with Balfour for the transgressions of 
his driver (" He cannot get over it," interjected Lady Kelvin). He 
is rather smitten with the idea of a vast empire knit together for 
all purposes of mutual support and help, feeling, I think, that 
electrical communication has made this possible which was 
impossible before, and much wishing that when we gave autonomy 
to Canada and Australasia we had reserved a right to free trade 
with them. He wanted to know how the Education Act was 
working in England. I told him a little about our or rather your 
experiences (he is a very good listener when you tell him what 
he likes to hear, which is, I think, almost anything). He took me 
into his study, where was a wonderful model which I cannot 
explain, to show the supposed structure of atoms and their 
elasticity, and besides a small globe. This set him off on a 
denunciation of the great omission in modern education in not 
teaching the use of the globes, for which he says Huxley is partly 
responsible. " No plane map," he said " could give any one a 
notion of the world ; and with our Empire every English child," 
he said, "ought to be shown something of its extent." I said I 


would stir you up for our Failand school. " Tell her," he said, 
that I have a conscientious scruple against paying for education 
in geography without the use of the globes, and shall not pay the 
proportionate part of the rate." 

Of course he was full of radium ; indeed Dr. Watson said it 
was engrossing his thoughts, and was a real worry to him, as it 
seemed to him to imperil some of his conclusions as to matter. 
"The mystery of radium," Lord Kelvin said to me, "no doubt we 
shall solve it one day ; but the freedom of the will, that is a 
mystery of another kind." He had two specimens of radium : 
one, impure, given him by Mons. Curie in 1900, in a small glass 
tube which he carries in his waistcoat pocket ; the other, much 
purer, given him by Sir Wm. Crookes, which you observe through 
a magnifying glass. We went successively with him into his safe to 
see these specimens. It is a very dangerous thing, to judge by 
the stories we heard from him of Mons. Curie s fingers, and Dr. 
Waller s arm, on which a wound formed from inside outwards, a 
month after the application of a minute fragment of radium. 

He talked a good deal about the expression " the fortuitous 
concourse of atoms," which I thought was to be found in Cicero s 
De Natura Deorum. He asked me a question I could not 
answer whether Lucretius was edited by Cicero. 

From fortuitous concourse of atoms he went on to speak of 
the whole frame of the universe, and propounded a view which I 
only inadequately grasped. " If," he said, " there were a mass of 
matter a heap of stones at rest " (i.e. if I understood rightly, 
operated on by no force but what was inherent in it), " it would 
gather together in a system ; and if there were a second mass it 
would do the same. If they were identical the two would gather 
together, but if they were in any respect unequal the effect of 
attraction would result in rotation. From these simple materials 
the whole starry universe might," he said, " have been evolved. I 
do not often mention it," he said, "for it sounds atheistic, and I 
am a firm believer in design." 

He asked me whether I believed that other worlds than our 
own were inhabited. I naturally disclaimed expressing an opinion 
to him, and I found that he does not believe any other of the 
sun s planets to be inhabitable by life, but thinks there may be 
stellar planets in such a condition. 

A course of lectures on " Christian Apologetics " 
was given at University College, London, in May 
1903, the first of the course being on Present Day 
Rationalism, by the Rev. Professor Henslow. A 

VOL. II 2 L 


vote of thanks was moved by Lord Kelvin in a 
short speech which attracted much attention. The 
following is The Times report, as corrected by Lord 
Kelvin s own hand : 

Lord Kelvin, in moving a vote of thanks to the lecturer, 
said, " I wish to make a personal explanation with 
reference to Professor Henslow s mention of ether- 
granules. I had recently, at a meeting of the Royal 
Society of Edinburgh, occasion to make use of the 
expressions ether, atoms, electricity, and had been horri 
fied to read in the Press that I had put forward a hypo 
thesis of ether-atoms. Ether is absolutely non-atomic ; 
it is absolutely structureless and homogeneous. I am 
in thorough sympathy with Professor Henslow in the 
fundamentals of his lecture. I do not say that, with 
regard to the origin of life, science neither affirms nor 
denies creative power. Science positively affirms creative 
power. Science makes every one feel a miracle in him 
self. It is not in dead matter that we live and move and 
have our being, but in the creating and directive Power 
which science compels us to accept as an article of belief. 
We cannot escape from that conclusion when we study the 
physics and dynamics of living and dead matter all 
around. Modern biologists are coming once more to a 
firm acceptance of something beyond mere gravitational, 
chemical, and physical forces ; and that unknown thing is 
a vital principle. We have an unknown object put before 
us in science. In thinking of that object we are all 
agnostics. We only know God in His works, but we 
are absolutely forced by science to admit and to believe 
with absolute confidence in a Directive Power in an 
influence other than physical, or dynamical, or electrical 
forces. Cicero, editor of Lucretius, denied that men and 
plants and animals could have come into existence 
by a fortuitous concourse of atoms. There is nothing 
between absolute scientific belief in Creative Power and 
the acceptance of the theory of a fortuitous concourse of 


atoms. Just think of a number of atoms falling together 
of their own accord and making a crystal, a sprig of 
moss, a microbe, a living animal. I admire throughout 
the healthy, breezy atmosphere of free-thought in Pro 
fessor Henslow s lecture. Do not be afraid of being free 
thinkers. If you think strongly enough you will be forced 
by science to the belief in God, which is the foundation 
of all Religion. You will find science not antagonistic, 
but helpful to Religion. 

On the same day that this appeared Lord 
Kelvin sent to The Times the following amend 
ing letter : 


May 2 [1903]. 

SIR In your report of a few words which I said in 
proposing a vote of thanks to Professor Henslow for his 
lecture " On Present Day Rationalism " yesterday evening 
in University College, I find the following : " Was there 
anything so absurd as to believe that a number of atoms 
by falling together of their own accord could make a 
crystal, a sprig of moss, a microbe, a living animal ? " I 
wish to delete " a crystal," though no doubt your report 
of what I said is correct. Exceedingly narrow limits of 
time prevented me from endeavouring to explain how 
different is the structure of a crystal from that of any 
portion, large or small, of an animal or plant, or the 
cellular formation of which the bodies of animals and 
plants are made ; but I desired to point out that, while 
" fortuitous concourse of atoms " is not an inappropriate 
description of a crystal, it is utterly absurd in respect to 
the coming into existence, or the growth, or the continua 
tion of the molecular combinations presented in the 
bodies of living things. Here scientific thought is com 
pelled to accept the idea of Creative Power. Forty 
years ago I asked Liebig, walking somewhere in the 
country, if he believed that the grass and flowers which 
we saw around us grew by mere chemical forces. He 


answered, " NO, no more than I could believe that a book 
of botany describing them grew by mere chemical forces." 
Every action of human free-will is a miracle to physical 
and chemical and mathematical science. Yours faithfully, 


A correspondence followed in the columns of 
The Times. Sir William Thiselton-Dyer queried 
whether Lord Kelvin was better equipped than any 
person of average intelligence for dogmatic utterance 
on biological questions, and complained that he 
wipes out by a stroke of the pen the whole position 
won for us by Darwin. Criticising Liebig s denial 
that flowers grew by mere chemical forces, he asked, 
" By what force do they grow?" And mistaking 
the new vitalism for the old, he added : " If growth 
is to be accounted for by a vital principle/ this 
must be capable of quantitative measurement like 
any other force. If it is physical energy in another 
form, Liebig s dictum is futile. If not, organisms 
are not subject to the principle of the conservation 
of energy." * He overlooked the point that in the 
exercise of operations under the law of conservation 
of energy, the mere directing of a force which may 
vastly affect the result involves no necessary ex 
penditure of energy. The old vitalism assumed that 
there was, and failed to account for it. Mr. W. H. 
Mallock inquired, " Does the evolution of organic 
life does * nature red in tooth and claw suggest 
to Lord Kelvin, what it failed to suggest to Tenny 
son, that the source of life is a Power which is not 
only creative, but is also wise, loving, and just in 


every comprehensible sense?" He further asked, 
" But is human free-will a fact ? This is the great 
question which all the philosophers of the modern 
world have debated. The affirmative answer may 
be true ; but Lord Kelvin merely assumes that it is, 
and thus, so far as his recent letter goes, he seeks to 
reinforce our confidence in religion, not by meeting 
our difficulties, but by ignoring their existence." Sir 
John Burdon-Sanderson pointed out how Helm- 
holtz had given the death-blow to the old vitalism. 
Another correspondent quoted Darwin s own words : 
"If ever it is found that life can originate on this 
world, the vital phenomena will come under some 
general law of nature. Whether the existence of a 
conscious God can be proved from the existence of 
the so-called laws of nature (i.e. fixed sequence of 
events) is a perplexing question, on which I have 
often thought, but cannot see my way clearly." Sir 
E. Ray Lankester denied the statement that any 
modern biologist showed signs of coming to a belief 
in the existence of a vital principle. On the other 
hand, some of the religious papers criticised Lord 
Kelvin s speech adversely, saying that unfortunately 
there was a great gulf between Lord Kelvin s 
affirmation of belief in a creative and directive 
power and the expression of Christian belief that 
is found in the propositions of the Apostles Creed. 
Lord Kelvin returned no rejoinder to his critics 
of either school of thought. He was invited by the 
editor of the Hibbert Journal to write out his speech 
in enlarged form for publication. A like request 


for the Nineteenth Century was made by Sir James 
Knowles, who wrote : 

To my thinking there is nothing more important in 
these whirling times than an anchorage for faith, such as 
common sense and science can approve, and your speech 
seems to me to indicate just that sort of anchorage. It 
brings back to my mind what Tennyson used so often to 
say to me about his personal faith. 

Lord Kelvin consented, and sent to Sir James 
Knowles a version embodying the correction of his 
letter of May 2. 

Eighteen months later Lord Kelvin returned to 
the question in an Address on presenting the prizes 
to students in the Medical School of St. George s 
Hospital, on October 23, 1904. The main thought 
is given in the following extract : 

Let it not be imagined that any hocus-pocus of electri 
city or viscous fluids will make a living cell. Splendid 
and interesting work has recently been done in what was 
formerly called inorganic chemistry, a great French 
chemist taking the lead. This is not the occasion for a 
lecture on the borderland between what is called organic 
and what is called inorganic ; but it is interesting to 
know that materials belonging to the general class of 
food-stuffs, such as sugar, and what might also be called a 
food-stuff, alcohol, can be made out of the chemical 
elements. But let not youthful minds be dazzled by the 
imaginings of the daily newspapers, that because Berthelot 
and others have thus made food-stuffs they can make 
living things, or that there is any prospect of a process 
being found in any laboratory for making a living thing, 
whether the minutest germ of bacteriology or anything 
smaller or greater. There is an absolute distinction 
between crystals and cells. Anything that crystallizes 
may be made by the chemist. Nothing approaching to 


the cell of a living creature has ever yet been made. 
The general result of an enormous amount of exceedingly 
intricate and thorough-going investigation by Huxley and 
Hooker and others of the present age, and by some of 
their predecessors in both the nineteenth and eighteenth 
centuries, is that no artificial process whatever can make 
living matter out of dead. This is vastly beyond the 
subject of the chemical laboratory, vastly beyond my own 
subject of physics or of electricity beyond it in depth of 
scientific significance and in human interest. 

His own suggestion in 1871 of a possible intro 
duction of life to this globe by meteoric sources, 
was often misunderstood or mis - stated. To a 
correspondent who wrote to him on this topic he 
replied in 1886 : 

The " star germ theory " which I put forward as a 
possibility does not in the slightest degree involve or 
suggest the origination of life without creative power, and 
is not in any degree antagonistic to, or out of harmony 
with, Christian belief. 

To another correspondent, in March 1887, he 
wrote : 

I think you will find nothing contrary to the Bible in 
the suggestion that some of the life at present on the 
earth may have come from seeds sown by meteoric stones. 
I have never thrown it out as more than a hypothesis 
that even so much was the case. But even if some of the 
living things on the earth did originate in that way so far 
as the earth is concerned, the origin of the species else 
where in the universe cannot have come about through 
the functions of dead matter ; and to our merely scientific 
judgment the origin of life anywhere in the universe seems 
absolutely to imply creative power. I believe that the 
more thoroughly science is studied the further does it 
take us from anything comparable to atheism. 


Almost at the close of his life the following note 
was dictated by Lord Kelvin in reply to a corre 
spondent in reference to a statement that " every 
body knows Lord Kelvin s theory of life." 

It is not quite true that everybody knows Lord 
Kelvin s theory, because certainly Lord Kelvin himself 
does not know it. He has put forward various suggestions 
at different times towards a Theory of Matter, but has 
never settled any in his own mind that could be called a 
new theory even of dead matter. The relations of matter 
and life are infinitely too complex for the human mind to 
understand. Science brings us face to face with creative 
power in the beginning of life on this earth and its 

Lord Kelvin had a whole-hearted detestation of 
spiritualism and all that pertains to it ; and would 
often go out of his way to denounce " that wretched 
superstition." He had seen its disastrous effects on 
his partner Varley. In the Address at the Midland 
Institute, Birmingham, in 1883 (p. 798), on the 
41 Six Gateways of Knowledge," he spoke thus : 

Now I have hinted at a possible seventh sense a 
magnetic sense and though out of the line I propose to 
follow, and although time is precious, and does not permit 
much of digression, I wish just to remove the idea that I 
am in any way suggesting anything towards that wretched 
superstition of animal magnetism, and table-turning, and 
spiritualism, and mesmerism, and clairvoyance, and spirit- 
rapping, of which we have heard so much. There is no 
seventh sense of the mystic kind. Clairvoyance, and the 
like, are the result of bad observation chiefly ; somewhat 
mixed up, however, with the effects of wilful imposture, 
acting on an innocent, trusting mind. But if there is not 
a distinct magnetic sense, I say it is a very great wonder 
that there is not Popular Lectures, vol. i. p. 258. 


To a correspondent, in March 1891, he wrote : 

You are perfectly right in your views about spiritualism 
and animal magnetism. There is no such thing as animal 
magnetism or any other influence, with which a table 
may be charged and in virtue of which it can be lifted, 
attracted, or repelled, or in any way influenced, without 
distinct mechanical action upon it. Faraday made an 
experimental examination of table-turning and found that 
the observed motions of the table were produced by the 
hands of the people touching it. The whole subject of 
spiritualism and animal magnetism is a tissue of super 
stition fostered by imposture. 

Lord Kelvin was very fond of animal pets. His 
parrots have several times been mentioned. He 
had a horror of unnecessary slaughter of creatures, 
particularly of birds. He once seized the arm of a 
man who, while on board his yacht, was shooting a 
sea-gull, and he protested indignantly against such 
wanton cruelty. 

On one occasion, while he was President of the 
Edinburgh Royal Society, a paper was read re 
counting certain experiments on living animals, 
experiments which seemed to him to exceed any 
scientific necessity. The next day there appeared 
in the Scotsman the following letter of protest : 

March 6, 1877. 

SIR In your print of this morning I see a report of 
Professor Rutherford s paper on " The Secretion of Bile," 
read at the meeting of the Royal Society yesterday 
evening, when, as president, I was in the chair. As 
chairman I did not feel that I had the right to express 
my opinion that experiments involving such torture to 
so large a number of sentient and intelligent animals are 


not justifiable by either the object proposed, or the results 
obtained, or obtainable, by such an investigation as that 
described by Professor Rutherford. I feel this opinion 
very strongly, after many years serious consideration of 
the general question of the advisableness or justifiableness 
of experiments involving cruel treatment of the lower 
animals. I trust you will kindly give me this opportunity 
of expressing it, as my presence without protest yesterday 
evening might seem to imply that I approved of the 
experiments which were described. I am, etc., 


Professor of Natural Philosophy 

in Glasgow University. 

Though on this occasion he took an unusual 
course, he admitted that for adequate cause shown, 
vivisection was justifiable. His opposition was 
limited to such vivisection as was not justified by 
the acquisition of new knowledge. To the total 
suppression of vivisection he was also opposed, as 
the following letter to the Secretary of the Society 
for the Protection of Animals shows : 

March 21, 1885. 

DEAR SIR When applied to several years ago to 
join in a movement to obtain the absolute prohibition of 
vivisection, I refused to do so, and I still feel that I 
cannot approve of this movement. As I see the Society 
for the Protection of Animals liable to Vivisection has 
become united to the International Association for the 
Total Suppression of Vivisection, I feel that I cannot 
longer continue to be a vice-president, and I therefore 
request that you will take my name off the list of vice- 
presidents. Yours truly, WILLIAM THOMSON. 

Although nothing was more characteristic of 
Lord Kelvin than his intense passion for making 


scientific calculations, his incessant and laborious 
devotion to the deepest problems of physics did 
not prevent him from having other enjoyments and 
occupations. If he read little, he appreciated what 
he read. He was fond of sea-stories and of novels 
bearing on sea-faring life. To the sea, and all that 
pertains to seamanship, he was devoted, as we have 
seen ; and sailing was his truest recreation. He 
was fond of sunshine. He hated to have the blinds 
in a room lowered, even partially, and from a boy had 
the habit of pulling them up to let in more sunlight. 

Himself childless, he was fond of little children. 
He liked to take them on his knee and show them 
his repeater watch ; and it was delightful to see 
him chatting with some small boy or little babbling 
maid, asking questions of them, and drawing out 
their childish answers. 

When he became famous, as the world reckons 
fame, he had no desire to be lionized by society or 
courted by wealthy parvenus. If any of these self- 
seeking persons forced themselves on his company 
he was never discourteous, but shrunk into a seem 
ing shyness. Exacting as he was in all pertaining 
to his work, and more exacting on himself and his 
own assistants than on any one else, he was essen 
tially of a considerate and gentle turn of mind 
towards others. 

Once the late Astronomer Royal had written 
an adverse criticism of one of his scientific works, 
in which his assistant was Ewing (afterwards 
Professor at Cambridge, now Director of Naval 


Education), at that time a youth of twenty-one. 
The Astronomer Royal s condemnation rested upon 
a misapprehension, and Ewing, eager to correct it, 
wrote to his chief asking leave to publish a reply. 
" By all means answer/ telegraphed Lord Kelvin, 
" but don t hit too hard. Remember he is four times 
as old as you. " 

Lord Kelvin s aversion from controversy in 
matters of scientific import has been several times 
shown (see pp. 291, 383, 449). His rebuke to Edison 
in 1878 for accusing certain English electricians 
of piracy and bad faith in the invention of the 
microphone, is well known. He exerted himself on 
more than one occasion to avert public controversy 
as to priority in scientific discovery, but was most 
punctilious in acknowledging the priority of others 
wherever his own investigations came into question. 
Nothing could exceed the quiet courtesy and kindli 
ness with which he treated younger men who 
brought to him the results of their own efforts in 
scientific research. His consideration in little things 
is illustrated by the following personal narrative 
communicated by Professor J. D. Cormack, now of 
University College, London : 

In 1884 the University of Heidelberg, at its tercenten 
ary celebrations, desiring to confer an honorary degree upon 
Sir William Thomson, and finding that the only one at 
their disposal which he did not already possess was that 
of Doctor of Medicine, accordingly presented him with 
that diploma. On the very day on which it arrived his 
kindly eye noticed the indisposition of his lecture -room 
assistant, and thereupon he wrote out his first prescription 


in proper language and form. Nature was the remedy 
and a week the dose. 

nj ftM ^ 

From the possession of this diploma arose an 
amusing scene in 1893, when Lord Kelvin was 
giving evidence in the law courts in the notorious 
4 electric belt" case. The learned counsel (now 
Lord Chief Justice of England) who was to cross- 
question him, opened fire by remarking that he 
presumed his Lordship s numerous qualifications did 
not include any medical ones. " I am M.D. of the 
University of Heidelberg," replied Lord Kelvin 
quietly ; while a ripple of laughter went round the 

Once when a wild tale appeared in a Dundee 
paper about Lord Kelvin swearing at a student 
who had thrown a missile at his head, Professor 
Ewing wrote an indignant contradiction, and sent 
him a copy of his letter. Lor